Merge pull request 'Launch a whole series or a single season, as a watch or lounge party' (#30) from feat/launch-whole-series into master

- lounge parties can now be created from one season (source type
  "season", keeping seriesId/seasonNumber) as well as a whole series
- POST /api/parties accepts a Series id (every season from S1E1) and a
  Season id (that season only); series tiles get a launch button
- whole-series queues skip specials (season 0, sorted first by Emby) -
  pure seriesQueueFrom/seasonQueue in CatalogService, unit-tested, also
  used by the "from this episode" path
- series page: "Lancer toute la série" + "Créer une lounge party" in the
  header, "Lancer cette saison" + "Lounge party de cette saison" above
  the selected season's episodes

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.forgejo/workflows/publish-docker.yml

@@ -55,13 +55,16 @@ jobs:
       # node:20-alpine n'a pas git préinstallé - même approche de clone
       # manuel que le job publish (pas d'actions/checkout, action JS qui a
       # ses propres soucis dans les conteneurs Alpine minimalistes ici).
+      # Sur une PR, `ref_name` vaut le numéro de la PR (ex. `29`), qui n'est
+      # pas une ref récupérable ("couldn't find remote ref 29") : on récupère
+      # alors la branche source de la PR (`head_ref`, vide hors PR).
       - name: Récupérer les sources
         run: |
           set -eu
           apk add --no-cache git
           git init -q
           git remote add origin "${{ github.server_url }}/${{ github.repository }}.git"
-          git fetch -q --depth 1 origin "${{ github.ref_name }}"
+          git fetch -q --depth 1 origin "${{ github.head_ref || github.ref_name }}"
           git checkout -q FETCH_HEAD
 
       - name: Serveur - installer les dépendances

.gitignore

@@ -21,6 +21,9 @@ server/dist/
 client/dist/
 *.tsbuildinfo
 
+## Runtime data (static watch parties - see server/src/services/StaticPartyStore.ts)
+data/
+
 ## OS cruft
 .DS_Store
 Thumbs.db

README.md

@@ -159,7 +159,7 @@ server/           Node.js + Express + Socket.IO backend: proxies ALL Emby
                   tsc to server/dist.
   src/index.ts                    Express app + route wiring only - thin,
                                    delegates to the services below
-  src/config.ts                   env-derived config (EMBY_SERVER_URL, PORT)
+  src/config.ts                   env-derived config (EMBY_SERVER_URL, PORT, DATA_DIR)
   src/types.ts                    shared interfaces (Party, ItemDto, the
                                    Socket.IO event maps, ...)
   src/Logger.ts                   party/stream lifecycle logging
@@ -245,9 +245,14 @@ build stage, so nothing needs building beforehand:
 
 ```bash
 docker build -f server/Dockerfile -t watchparty .
-docker run -d --name watchparty -p 3000:3000 -e EMBY_SERVER_URL=https://theater.media.kyuno.fr watchparty
+docker run -d --name watchparty -p 3000:3000 -v "$(pwd)/data:/data" -e EMBY_SERVER_URL=https://theater.media.kyuno.fr watchparty
 ```
 
+The `/data` volume holds the static (persistent) watch parties
+(`DATA_DIR`, see [`spec/static-watch-party.md`](spec/static-watch-party.md)).
+Without it they're lost whenever the container is recreated.
+`docker-compose.yml` already mounts it.
+
 Then put it behind your existing reverse proxy like everything else
 (`theater.media.kyuno.fr`, `git.dev.kyuno.fr`, ...), e.g.
 `watchparty.kyuno.fr` → `http://<container>:3000`.
@@ -328,6 +333,85 @@ Then put it behind your existing reverse proxy like everything else
       as its own always-on-top bar, duplicating the cast icon and
       overlapping the new bottom bar in fullscreen) in favor of fully
       custom play/pause, a seek bar, and mute — see docs/architecture.md
+- [x] Sticky search bar on the library/artist/album pages, and letting
+      anyone seek within the current music track (same no-host-check
+      model pause/resume already had) — see docs/architecture.md
+- [x] Skip intro / jump to next episode at end credits, using Emby's own
+      native marker detection (`EnableMarkerDetection` + its "Detect
+      Episode Intros" task) rather than building fingerprinting
+      ourselves — see docs/architecture.md
+- [x] Report each party member's own playback to Emby's real Sessions
+      API (`/Sessions/Playing`, `/Progress`, `/Stopped`), so the admin
+      dashboard sees watch-party streams the same way it sees a native
+      client's — one session per member, under their own account — see
+      docs/architecture.md
+- [x] Queue a whole album, or an artist's entire discography, in one
+      action — resolved server-side (one atomic operation, not one
+      request per track) the same way launching a playlist already
+      expands into everything it contains — see docs/architecture.md
+- [x] Picture-in-picture for the video player (standard
+      `requestPictureInPicture`, confirmed present on Android Chrome) —
+      asked for directly for mobile, where there's no second window to
+      put this app in while switching apps — see docs/architecture.md
+- [x] Installable as a PWA (manifest + icons, standalone display,
+      no service worker — this app has nothing worth caching offline)
+      — see docs/architecture.md
+- [x] Mobile navigation redesigned as a bottom sheet (Accueil /
+      Bibliothèques / Listes de lecture) instead of a horizontally
+      scrolling sidebar — see docs/architecture.md
+- [x] Music UI reworked to look like a music app instead of reusing
+      movie-poster tiles — circular artist tiles, square album tiles,
+      a real hero header, and a mobile "now playing" full-screen player
+      — see docs/architecture.md
+- [x] Mobile menu's bottom sheet is now swipe-to-close (a real drag
+      handle, not just a decorative grabber) instead of fighting the
+      browser's own pull-to-refresh gesture — see docs/architecture.md
+- [x] Every blocking `alert()` (host handoff, every "couldn't start/join
+      a party" error) replaced with a light, auto-dismissing toast — see
+      docs/architecture.md
+- [x] Library/artist grid tiles shrink fluidly on a narrow phone instead
+      of a fixed 160px floor collapsing to one column per row — see
+      docs/architecture.md
+- [x] Library page title now stays pinned alongside the search bar while
+      scrolling, instead of just the search bar — see docs/architecture.md
+- [x] Library alphabet index: sticky per-letter section headings plus a
+      right-edge A-Z rail to jump straight to one, drag-to-scrub like
+      iOS's own Contacts — see docs/architecture.md
+- [x] Fixed the alphabet index's headers landing in the wrong order —
+      it was bucketing by display name instead of Emby's own SortName,
+      so an article-stripped title ("The ...") threw a whole run off —
+      see docs/architecture.md
+- [x] Fixed the music bar's queue popup — a missing `position` broke
+      the desktop layout when opened and left it unclosable on mobile
+      (its own close button was reachable now) — see docs/architecture.md
+- [x] Fixed library tile buttons rendering on top of the sticky header
+      while scrolling — an equal z-index tie that a scrolling tile won
+      — see docs/architecture.md
+- [x] Fixed the music bar's desktop layout for real — the progress bar
+      was missing a grid-column span, so it (and not just the queue
+      popup above) was still squeezed and wrapping controls onto a
+      second row — see docs/architecture.md
+- [x] Fixed an album's track rows collapsing to 3 lines on mobile —
+      there was always room for one, the breakpoint just assumed
+      otherwise — see docs/architecture.md
+- [x] A mobile banner nudging an install of the PWA — the real
+      Chrome/Android install prompt, manual instructions on iOS Safari
+      (no such prompt exists there) — see docs/architecture.md
+- [x] Linked whatever's playing (video or music) to the OS's own media
+      controls (Windows' SMTC, macOS' Now Playing, ...) — title/artwork,
+      play/pause/seek/next — see docs/architecture.md
+- [x] Fixed switching a party between devices leaving both "on the
+      session" with no working controls — the old device never reacted
+      to being kicked, and the leave route had no way to tell a stale
+      device apart from the current one — see docs/architecture.md
+- [x] Fixed a track started directly (not via its album/artist) never
+      falling back to its album's artwork — see docs/architecture.md
+      (probably not the whole "images are hard to find" story — flagged
+      there)
+- [x] Fixed the music bar's mobile now-playing screen not fitting a
+      phone rotated to landscape — the art now sits beside the title
+      instead of above it, sized off the viewport height instead of a
+      fixed width-based cap — see docs/architecture.md
 - [ ] Try a full party end-to-end with two real accounts (still the main gap)
 - [ ] Try casting to a real Chromecast (only the SDK's own bootstrap is
       confirmed here — no real device/session)

client/build.mjs

@@ -11,7 +11,7 @@
 //   npm run watch   -> rebuilds on save, for local dev (see README's
 //                      Running locally section)
 import * as esbuild from 'esbuild';
-import { copyFileSync, mkdirSync } from 'fs';
+import { copyFileSync, cpSync, mkdirSync } from 'fs';
 import path from 'path';
 import { fileURLToPath } from 'url';
 
@@ -20,6 +20,11 @@ const outdir = path.join(here, 'dist');
 
 mkdirSync(outdir, { recursive: true });
 copyFileSync(path.join(here, 'src', 'index.html'), path.join(outdir, 'index.html'));
+// PWA manifest + icons (manifest.webmanifest, icons/*) - see
+// docs/architecture.md's "Progressive Web App" section. Copied wholesale
+// rather than named file-by-file like index.html above, so adding another
+// icon later needs no build.mjs change.
+cpSync(path.join(here, 'src', 'public'), outdir, { recursive: true });
 
 const buildOptions = {
   entryPoints: [path.join(here, 'src', 'app.ts')],

client/src/alphaIndex.css

@@ -0,0 +1,81 @@
+/* ---- Alphabet index: sticky letter headings inside .grid + the
+   right-edge A-Z rail that jumps to one - see alphaIndex.ts. ---- */
+
+/* Full-width row inside tiles.css's own .grid (still just
+   `repeat(auto-fill, minmax(...))` - unchanged), interspersed with
+   normal tile children rather than a separate nested grid per letter. */
+.letterHeading {
+  grid-column: 1 / -1;
+  position: sticky;
+  top: var(--section-sticky-top, 0px);
+  /* Same z-index: 3 as views/library/Library.css's own .libraryHeader,
+     and for the identical reason: tiles.css's .tileOverlay is z-index:
+     2, and a tie there breaks toward whichever renders later in the
+     DOM - a tile, always after this heading. */
+  z-index: 3;
+  background: var(--bg);
+  color: var(--accent-bright);
+  font-size: 13px;
+  font-weight: 700;
+  padding: 6px 2px;
+  scroll-margin-top: var(--section-sticky-top, 0px);
+}
+
+.alphaRail {
+  position: fixed;
+  right: 2px;
+  z-index: 4;
+  width: 20px;
+  display: flex;
+  flex-direction: column;
+  justify-content: space-evenly;
+  align-items: center;
+  padding: 6px 0;
+  /* This app's own pointer handlers (alphaIndex.ts) drive the drag -
+     without this, the browser reads a vertical drag on a touch device
+     as its own gesture (scroll/pull-to-refresh) instead, the same
+     conflict shell/Shell.css's mobile nav sheet had to solve once
+     already for its own drag handle. */
+  touch-action: none;
+}
+
+.railLetter {
+  font-size: 9px;
+  font-weight: 700;
+  color: var(--muted);
+  line-height: 1;
+  width: 100%;
+  text-align: center;
+  user-select: none;
+}
+
+.railLetter.active { color: var(--accent-bright); }
+.railLetterEmpty { color: rgba(255, 255, 255, .15); }
+
+.alphaBubble {
+  position: fixed;
+  top: 50%;
+  left: 50%;
+  transform: translate(-50%, -50%) scale(.7);
+  width: 84px;
+  height: 84px;
+  border-radius: 50%;
+  background: rgba(20, 18, 22, .88);
+  border: 1px solid rgba(255, 255, 255, .12);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 36px;
+  font-weight: 700;
+  color: var(--accent-bright);
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity .12s ease, transform .12s ease;
+  z-index: 6;
+}
+
+.alphaBubble.show { opacity: 1; transform: translate(-50%, -50%) scale(1); }
+
+@media (prefers-reduced-motion: reduce) {
+  .alphaBubble { transition: none; }
+}

client/src/alphaIndex.ts

@@ -0,0 +1,218 @@
+// Alphabet index for a library grid: sticky per-letter section headings
+// inside the grid itself, plus a right-edge A-Z rail to jump straight to
+// one - see docs/architecture.md. Library-only for now (that's the only
+// page that asked), but nothing below assumes anything Library-specific
+// beyond the two elements it measures (.libraryHeader, shell/Shell.html's
+// .bottomStack) - reusable elsewhere later without change.
+import './alphaIndex.css';
+import { tileHtml } from './tiles';
+import type { CleanupFn } from './router';
+import type { ItemDto } from './types';
+
+const ALL_BUCKETS = ['#', ...Array.from({ length: 26 }, (_, i) => String.fromCharCode(65 + i))];
+
+/**
+ * An item's index bucket: the first letter of its `sortName` - NOT
+ * `name` - with accents folded to their base (so "Écho" lands on "E",
+ * matching how a French speaker would expect the index to group it, not
+ * off in its own "É"/"#" bucket). Anything else (a digit, empty) falls
+ * back to "#".
+ *
+ * `sortName`, deliberately, not the display name: `items` arrives in
+ * Emby's own SortName order (getLibraryItems/getArtists both request
+ * `SortBy: SortName`), and that order strips leading articles ("Le
+ * Voyage" sorts as "Voyage") - bucketing by the raw display name instead
+ * put a "L" heading in the middle of a "V" run the one time an article
+ * did that, reported directly as headers in no sensible order at all.
+ * Bucketing by the exact same key Emby used to order the array is what
+ * guarantees a bucket is always one contiguous run, not a guess that it
+ * happens to line up.
+ */
+function bucketFor(item: ItemDto): string {
+  const base = (item.sortName || item.name || '').trim().normalize('NFD').replace(/[̀-ͯ]/g, '');
+  const c = base.charAt(0).toUpperCase();
+  return c >= 'A' && c <= 'Z' ? c : '#';
+}
+
+/**
+ * Same job as tiles.ts's renderTilesInChunks (chunked insertAdjacentHTML,
+ * not one big innerHTML write - see that function's own comment for why
+ * that matters on a 1000+-item library), plus a `.letterHeading` inserted
+ * right before the first tile of each new bucket. `items` is assumed
+ * already ordered by `sortName` (see bucketFor) - a chunk boundary
+ * landing mid-bucket is fine, it's still one contiguous run either way.
+ */
+export function renderGroupedTilesInChunks(container: HTMLElement, items: ItemDto[], chunkSize = 40): void {
+  container.innerHTML = '';
+  let i = 0;
+  let lastBucket: string | null = null;
+  function renderNextChunk(): void {
+    const chunk = items.slice(i, i + chunkSize);
+    if (!chunk.length) return;
+    let html = '';
+    for (const item of chunk) {
+      const bucket = bucketFor(item);
+      if (bucket !== lastBucket) {
+        html += `<div class="letterHeading" data-letter-anchor="${bucket}">${bucket}</div>`;
+        lastBucket = bucket;
+      }
+      html += tileHtml(item);
+    }
+    container.insertAdjacentHTML('beforeend', html);
+    i += chunkSize;
+    if (i < items.length) setTimeout(renderNextChunk, 0);
+  }
+  renderNextChunk();
+}
+
+/**
+ * Hides a `.letterHeading` whenever every tile in its run is currently
+ * `.hide`'d by tiles.ts's wireSearchFilter - without this, searching
+ * down to matches in only one bucket would leave every other bucket's
+ * heading floating above nothing. Call once, after wireSearchFilter
+ * itself is wired to the same input (listener order = registration
+ * order, so this always runs after .hide has already been updated).
+ */
+export function wireSectionSearchSync(input: HTMLInputElement, grid: HTMLElement): void {
+  input.addEventListener('input', () => {
+    grid.querySelectorAll<HTMLElement>('.letterHeading').forEach((heading) => {
+      let sib = heading.nextElementSibling;
+      let anyVisible = false;
+      while (sib && !sib.classList.contains('letterHeading')) {
+        if (!sib.classList.contains('hide')) { anyVisible = true; break; }
+        sib = sib.nextElementSibling;
+      }
+      heading.classList.toggle('hide', !anyVisible);
+    });
+  });
+}
+
+/**
+ * The right-edge A-Z rail: tap or drag it to jump the page scroll to a
+ * letter's section heading, with a big center-screen bubble showing the
+ * current letter while doing so (fades out on release) - same
+ * pointerdown/move/up-on-a-dedicated-element and touch-action: none shape
+ * as shell/Shell.ts's own nav-sheet grabber handle, so a vertical drag
+ * here doesn't get read as the browser's pull-to-refresh either. Letters
+ * with nothing in `items` render dimmed and inert.
+ *
+ * The rail and every letterHeading's sticky offset are measured live off
+ * .libraryHeader and .bottomStack rather than hardcoded: .bottomStack
+ * (the music bar) can appear/resize while this page stays open - a
+ * listen party starting - and it floats above the grid on desktop too,
+ * not just mobile, so both need to stay clear of it regardless of
+ * breakpoint. `getComputedStyle(libraryHeader).top` picks up whichever
+ * of Library.css's own two breakpoint values is active without this
+ * module needing to duplicate that 720px rule itself.
+ *
+ * Returns a CleanupFn (see router.ts) - the two ResizeObservers and the
+ * window-level scroll/resize listeners this sets up would otherwise keep
+ * running after the user navigates away, the exact leak class
+ * docs/architecture.md already documents this app getting bitten by
+ * once before.
+ */
+export function wireAlphaRail(root: HTMLElement, grid: HTMLElement, items: ItemDto[]): CleanupFn {
+  const present = new Set(items.map((it) => bucketFor(it)));
+  const libraryHeader = root.querySelector('.libraryHeader') as HTMLElement;
+  const bottomStack = document.querySelector('.bottomStack') as HTMLElement | null;
+
+  const rail = document.createElement('div');
+  rail.className = 'alphaRail';
+  rail.innerHTML = ALL_BUCKETS.map((letter) => {
+    const has = present.has(letter);
+    return `<span class="railLetter${has ? '' : ' railLetterEmpty'}" data-letter="${letter}" role="button" aria-label="Aller à ${letter}" aria-disabled="${!has}">${letter}</span>`;
+  }).join('');
+  root.appendChild(rail);
+
+  const bubble = document.createElement('div');
+  bubble.className = 'alphaBubble';
+  root.appendChild(bubble);
+
+  function recomputeOffsets(): void {
+    const top = parseFloat(getComputedStyle(libraryHeader).top) || 0;
+    const stickyBottom = top + libraryHeader.offsetHeight;
+    grid.style.setProperty('--section-sticky-top', `${stickyBottom}px`);
+    rail.style.top = `${stickyBottom}px`;
+    rail.style.bottom = `${bottomStack ? bottomStack.offsetHeight : 0}px`;
+  }
+  recomputeOffsets();
+
+  const resizeObserver = new ResizeObserver(recomputeOffsets);
+  resizeObserver.observe(libraryHeader);
+  if (bottomStack) resizeObserver.observe(bottomStack);
+  window.addEventListener('resize', recomputeOffsets);
+
+  let bubbleFadeTimer: ReturnType<typeof setTimeout> | null = null;
+  function showBubble(letter: string): void {
+    bubble.textContent = letter;
+    bubble.classList.add('show');
+    if (bubbleFadeTimer) clearTimeout(bubbleFadeTimer);
+  }
+  function scheduleHideBubble(): void {
+    if (bubbleFadeTimer) clearTimeout(bubbleFadeTimer);
+    bubbleFadeTimer = setTimeout(() => bubble.classList.remove('show'), 260);
+  }
+
+  function setActive(letter: string): void {
+    rail.querySelectorAll('.railLetter').forEach((el) => {
+      el.classList.toggle('active', el.getAttribute('data-letter') === letter);
+    });
+  }
+
+  function letterAt(clientY: number): string {
+    const rect = rail.getBoundingClientRect();
+    const ratio = Math.min(1, Math.max(0, (clientY - rect.top) / rect.height));
+    return ALL_BUCKETS[Math.min(ALL_BUCKETS.length - 1, Math.floor(ratio * ALL_BUCKETS.length))] as string;
+  }
+
+  function jumpTo(letter: string): void {
+    setActive(letter);
+    showBubble(letter);
+    const target = grid.querySelector(`[data-letter-anchor="${letter}"]`);
+    if (target) target.scrollIntoView({ block: 'start' });
+  }
+
+  let dragging = false;
+  function onPointerDown(e: PointerEvent): void {
+    dragging = true;
+    rail.setPointerCapture(e.pointerId);
+    jumpTo(letterAt(e.clientY));
+  }
+  function onPointerMove(e: PointerEvent): void {
+    if (!dragging) return;
+    jumpTo(letterAt(e.clientY));
+  }
+  function endDrag(): void {
+    if (!dragging) return;
+    dragging = false;
+    scheduleHideBubble();
+  }
+  rail.addEventListener('pointerdown', onPointerDown);
+  rail.addEventListener('pointermove', onPointerMove);
+  rail.addEventListener('pointerup', endDrag);
+  rail.addEventListener('pointercancel', endDrag);
+
+  let scrollSpyScheduled = false;
+  function onWindowScroll(): void {
+    if (dragging || scrollSpyScheduled) return;
+    scrollSpyScheduled = true;
+    requestAnimationFrame(() => {
+      scrollSpyScheduled = false;
+      const stickyBottom = parseFloat(grid.style.getPropertyValue('--section-sticky-top')) || 0;
+      let current = ALL_BUCKETS[0] as string;
+      grid.querySelectorAll<HTMLElement>('[data-letter-anchor]').forEach((el) => {
+        if (el.getBoundingClientRect().top - stickyBottom <= 4) current = el.getAttribute('data-letter-anchor') as string;
+      });
+      setActive(current);
+    });
+  }
+  window.addEventListener('scroll', onWindowScroll, { passive: true });
+  setActive(ALL_BUCKETS[0] as string);
+
+  return () => {
+    resizeObserver.disconnect();
+    window.removeEventListener('resize', recomputeOffsets);
+    window.removeEventListener('scroll', onWindowScroll);
+    if (bubbleFadeTimer) clearTimeout(bubbleFadeTimer);
+  };
+}

client/src/api/embyApi.ts

@@ -3,7 +3,7 @@
 // module just wraps fetch calls to our own /api/* routes. See
 // docs/architecture.md for why this changed from the first version (CORS,
 // plus not wanting the browser to hold an Emby token at all).
-import type { ItemDto, LibraryDto, PlaybackOptionsDto, SeasonDto } from '../types';
+import type { ItemDto, LibraryDto, PlaybackMarkersDto, PlaybackOptionsDto, SeasonDto } from '../types';
 
 async function apiFetch<T>(path: string, options: RequestInit = {}): Promise<T> {
   const res = await fetch(path, {
@@ -116,6 +116,10 @@ export function getPlaybackOptions(itemId: string): Promise<PlaybackOptionsDto>
   return apiFetch(`/api/catalog/item/${itemId}/playback-options`);
 }
 
+export function getPlaybackMarkers(itemId: string): Promise<PlaybackMarkersDto> {
+  return apiFetch(`/api/catalog/item/${itemId}/markers`);
+}
+
 /** The party's own shared Emby stream (server/src/services/
  *  PartyStreamService.ts) - one negotiated PlaybackInfo session reused
  *  by every member, instead of each viewer's own <video>/<audio>

client/src/api/party.ts

@@ -39,8 +39,14 @@ export function joinParty(partyId: string): Promise<PartyPublicState> {
   return apiFetch(`/api/parties/${encodeURIComponent(partyId)}/join`, { method: 'POST' });
 }
 
+/** Sends this device's own deviceId so the server can tell a stale
+ *  device (already replaced by a takeover on another one - see
+ *  getDeviceId's own comment) apart from the currently-active one, the
+ *  same way the socket "join"/"leave"/"disconnect" handlers already do
+ *  via the live connection itself - a REST call has no connection to
+ *  compare, so this is what lets the server apply that same guard here. */
 export function leaveParty(partyId: string): Promise<{ ok: true }> {
-  return apiFetch(`/api/parties/${partyId}/leave`, { method: 'POST' });
+  return apiFetch(`/api/parties/${partyId}/leave`, { method: 'POST', body: JSON.stringify({ deviceId: getDeviceId() }) });
 }
 
 export function getParty(partyId: string): Promise<PartyPublicState> {
@@ -61,6 +67,21 @@ export function addTrackToQueue(partyId: string, track: MusicTrackInput): Promis
   return apiFetch(`/api/parties/${partyId}/tracks`, { method: 'POST', body: JSON.stringify(track) });
 }
 
+/**
+ * Music only: queues `itemId` into a party's shared queue, whatever it
+ * turns out to be - a single track queues itself, an album or an
+ * artist expands into every track inside it (see index.ts's
+ * resolveMusicTracksForItem) - the "add to queue" half of
+ * views/album's/views/artist's own whole-album/whole-discography
+ * button (createParty(itemId) is the other half, for when there's no
+ * party active yet - see Album.ts/Artist.ts). Distinct from
+ * addTrackToQueue above, which takes an already-built track object a
+ * caller has in hand rather than an id to resolve server-side.
+ */
+export function queueItem(partyId: string, itemId: string): Promise<PartyPublicState> {
+  return apiFetch(`/api/parties/${partyId}/queue`, { method: 'POST', body: JSON.stringify({ itemId }) });
+}
+
 /**
  * Mints a short-lived, party-scoped token a Chromecast can use to reach
  * this party's own shared stream routes, which otherwise only accept the
@@ -129,6 +150,9 @@ export interface PartyConnection {
   sendPlaystate(isPaused: boolean, positionTicks: number): void;
   /** Host-only: advance the party's queue (e.g. to the next episode). */
   next(): void;
+  /** Host-only: the last queued item played to its end - lets the server
+   *  count it as watched (there's no "next" to send for it). */
+  itemEnded(): void;
   /** Asks the host (and tells everyone else) "please pause". Video only -
    *  a music party has no host to ask, see voteSkip/setMusicPaused. */
   requestPause(): void;
@@ -140,6 +164,10 @@ export interface PartyConnection {
   voteSkip(): void;
   /** Music only: no host check server-side, unlike sendPlaystate above. */
   setMusicPaused(isPaused: boolean): void;
+  /** Music only: jump to `positionSeconds` in the current track - same
+   *  no-host-check treatment as setMusicPaused above (see
+   *  MusicQueueService.seek's own comment for why). */
+  seekMusic(positionSeconds: number): void;
   /** Re-sends "join" with force:true after the user confirms they want to
    *  disconnect their other device and take over here - call this from
    *  onDeviceConflict's handler once the user says yes. */
@@ -205,6 +233,9 @@ export function connectParty(partyId: string, callbacks: PartyConnectionCallback
     next() {
       socket.emit('next');
     },
+    itemEnded() {
+      socket.emit('itemEnded');
+    },
     requestPause() {
       socket.emit('requestPause');
     },
@@ -217,6 +248,9 @@ export function connectParty(partyId: string, callbacks: PartyConnectionCallback
     setMusicPaused(isPaused) {
       socket.emit('musicPlaystate', { isPaused });
     },
+    seekMusic(positionSeconds) {
+      socket.emit('musicSeek', { positionSeconds });
+    },
     confirmDeviceTakeover() {
       socket.emit('join', { partyId, deviceId, force: true });
     },

client/src/api/staticParty.ts

@@ -0,0 +1,74 @@
+// Static (persistent) watch parties - REST only, same origin, session
+// cookie auth (see embyApi.ts). A static party's live sessions are
+// ordinary parties: once one of these calls returns a partyId, everything
+// else goes through api/party.ts and the normal player, unchanged. See
+// server/src/services/StaticPartyService.ts and spec/static-watch-party.md.
+import type { StaticPartyDetailDto, StaticPartySummaryDto } from '../types';
+
+/** Same contract as api/party.ts's own helper: JSON in/out, the server's
+ *  `error` message thrown as-is (they're written to be shown to users). */
+async function apiFetch<T>(path: string, options: RequestInit = {}): Promise<T> {
+  let res: Response;
+  try {
+    res = await fetch(path, {
+      credentials: 'same-origin',
+      ...options,
+      headers: { 'Content-Type': 'application/json', ...(options.headers || {}) }
+    });
+  } catch (err) {
+    console.error('[staticParty] network error', path, err);
+    throw new Error('Serveur injoignable.');
+  }
+  if (!res.ok) {
+    const body = await res.json().catch(() => ({}));
+    console.warn('[staticParty] request failed', path, res.status, body.error);
+    throw new Error(body.error || `Request failed: ${res.status}`);
+  }
+  return res.json() as Promise<T>;
+}
+
+/** Every static watch party, with the viewer's own missed count. */
+export async function listStaticParties(): Promise<StaticPartySummaryDto[]> {
+  const data = await apiFetch<{ staticParties: StaticPartySummaryDto[] }>('/api/static-parties');
+  return data.staticParties;
+}
+
+/** Creates one from a series or a video playlist (`sourceId`). */
+export function createStaticParty(sourceId: string, name?: string): Promise<StaticPartyDetailDto> {
+  return apiFetch('/api/static-parties', { method: 'POST', body: JSON.stringify({ sourceId, name }) });
+}
+
+/** Everything about one static watch party, from the viewer's side. */
+export function getStaticParty(id: string): Promise<StaticPartyDetailDto> {
+  return apiFetch(`/api/static-parties/${encodeURIComponent(id)}`);
+}
+
+/** Become a member. */
+export function joinStaticParty(id: string): Promise<{ ok: true }> {
+  return apiFetch(`/api/static-parties/${encodeURIComponent(id)}/join`, { method: 'POST' });
+}
+
+/** Stop being a member (drops the viewer's own progress). */
+export function leaveStaticParty(id: string): Promise<{ ok: true }> {
+  return apiFetch(`/api/static-parties/${encodeURIComponent(id)}/leave`, { method: 'POST' });
+}
+
+/** Delete it for everyone - creator only. */
+export function deleteStaticParty(id: string): Promise<{ ok: true }> {
+  return apiFetch(`/api/static-parties/${encodeURIComponent(id)}`, { method: 'DELETE' });
+}
+
+/** "Marquer comme vu". */
+export function markStaticItemWatched(id: string, itemId: string): Promise<{ ok: true }> {
+  return apiFetch(`/api/static-parties/${encodeURIComponent(id)}/items/${encodeURIComponent(itemId)}/watched`, { method: 'POST' });
+}
+
+/** Launches the group's next session, or joins the one running. */
+export function startStaticSession(id: string): Promise<{ partyId: string }> {
+  return apiFetch(`/api/static-parties/${encodeURIComponent(id)}/session`, { method: 'POST' });
+}
+
+/** Catches up on `itemIds` - alone, or as a watch party others can join. */
+export function startCatchUp(id: string, itemIds: string[], mode: 'solo' | 'party'): Promise<{ partyId: string }> {
+  return apiFetch(`/api/static-parties/${encodeURIComponent(id)}/catch-up`, { method: 'POST', body: JSON.stringify({ itemIds, mode }) });
+}

client/src/app.ts

@@ -10,6 +10,8 @@ import { renderArtist } from './views/artist/Artist';
 import { renderAlbum } from './views/album/Album';
 import { renderPlaylist } from './views/playlist/Playlist';
 import { renderPartyPlayer } from './views/player/Player';
+import { renderStaticParty } from './views/staticParty/StaticParty';
+import { renderStaticParties } from './views/staticParties/StaticParties';
 
 route('/', () => navigate('/home'));
 route('/login', renderLogin);
@@ -20,6 +22,8 @@ route('/artist/:id', renderArtist);
 route('/album/:id', renderAlbum);
 route('/playlist/:id', renderPlaylist);
 route('/party/:id', renderPartyPlayer);
+route('/static', renderStaticParties);
+route('/static/:id', renderStaticParty);
 
 /**
  * Renders either the bare login screen or the full shell (sidebar +

client/src/index.html

@@ -4,6 +4,24 @@
   <meta charset="utf-8" />
   <meta name="viewport" content="width=device-width, initial-scale=1" />
   <title>Watch Party</title>
+
+  <!-- PWA - see docs/architecture.md's "Progressive Web App" section.
+       theme-color/background_color both come straight from base.css's
+       --bg-header/--bg (the manifest can't read CSS custom properties,
+       so these are duplicated by hand - if that palette ever changes,
+       update manifest.webmanifest to match). -->
+  <link rel="manifest" href="manifest.webmanifest" />
+  <meta name="theme-color" content="#221d24" />
+  <link rel="icon" type="image/png" href="icons/favicon.png" />
+
+  <!-- iOS ignores the manifest above for installed-app chrome - Safari
+       needs its own separate meta tags/link for the equivalent
+       standalone/home-screen-icon behavior. -->
+  <link rel="apple-touch-icon" href="icons/apple-touch-icon.png" />
+  <meta name="apple-mobile-web-app-capable" content="yes" />
+  <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent" />
+  <meta name="apple-mobile-web-app-title" content="Watch Party" />
+
   <link rel="stylesheet" href="app.css" />
   <script src="https://cdnjs.cloudflare.com/ajax/libs/hls.js/1.5.17/hls.min.js"></script>
   <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/4.7.5/socket.io.min.js"></script>

client/src/mediaSession.ts

@@ -0,0 +1,123 @@
+// System Media Transport Controls integration - Windows' own media-key
+// popup/taskbar overlay (also macOS' Now Playing widget, Android's
+// notification) - see docs/architecture.md. A thin wrapper around the
+// standard Media Session API, not a new abstraction of its own: every
+// function here is a one-line guard (`'mediaSession' in navigator`)
+// around the exact browser call, since Firefox has never implemented
+// this at all and this safely no-ops everywhere else it's missing too.
+// Shared by views/player/Player.ts (video) and musicBar/MusicBar.ts
+// (a listen party) - the two can never be active at once (starting/
+// joining either already leaves the other first), so there's no risk
+// of them fighting over this single global.
+
+export interface MediaSessionActions {
+  onPlay: () => void;
+  onPause: () => void;
+  /** Host-only for video (Player.ts checks isHost itself before acting -
+   *  this just delivers the OS's own seek gesture), unrestricted for
+   *  music (no host concept there). */
+  onSeek?: (seconds: number) => void;
+}
+
+/** Title/artist/album/art shown in the OS's own now-playing UI - artist
+ *  and album are meaningless for a video (pass '' for both), matching
+ *  how a movie has no equivalent fields in this app's own UI either. */
+export function setMediaSessionMetadata(title: string, artist: string, album: string, artworkUrl: string): void {
+  if (!('mediaSession' in navigator)) return;
+  navigator.mediaSession.metadata = new MediaMetadata({
+    title,
+    artist,
+    album,
+    artwork: artworkUrl ? [{ src: artworkUrl, sizes: '512x512', type: 'image/jpeg' }] : []
+  });
+}
+
+export function setMediaSessionPlaybackState(playing: boolean): void {
+  if (!('mediaSession' in navigator)) return;
+  navigator.mediaSession.playbackState = playing ? 'playing' : 'paused';
+}
+
+/** The OS's own scrubber - harmless to skip (not every browser/OS
+ *  combination renders one) but adds real functionality where it does.
+ *  Chrome throws if `duration` isn't a positive finite number, or if
+ *  `position` doesn't satisfy `0 <= position <= duration` - both
+ *  momentarily true the instant an item/track changes but the ticker
+ *  driving this hasn't caught up yet, so this is caught rather than
+ *  guarded field-by-field (the next tick corrects it either way). */
+export function setMediaSessionPositionState(duration: number, position: number): void {
+  if (!('mediaSession' in navigator) || !navigator.mediaSession.setPositionState) return;
+  if (!(duration > 0) || !isFinite(duration)) return;
+  try {
+    navigator.mediaSession.setPositionState({ duration, position: Math.max(0, Math.min(position, duration)), playbackRate: 1 });
+  } catch {
+    // See this function's own comment - a transient mismatch, not a real error.
+  }
+}
+
+/**
+ * Wired once per party lifetime (Player.ts's init(), MusicBar.ts's
+ * initMusicBar()) - the handlers themselves close over whatever local
+ * state they need (isHost, conn, ...) and read it fresh on every
+ * OS-triggered call, so this never needs re-wiring just because that
+ * state changed later (see Player.ts's own isHost, which does exactly
+ * that mid-session on a host handoff).
+ */
+export function setMediaSessionActionHandlers(actions: MediaSessionActions): void {
+  if (!('mediaSession' in navigator)) return;
+  navigator.mediaSession.setActionHandler('play', actions.onPlay);
+  navigator.mediaSession.setActionHandler('pause', actions.onPause);
+  if (actions.onSeek) {
+    const onSeek = actions.onSeek;
+    navigator.mediaSession.setActionHandler('seekto', (details) => {
+      if (details.seekTime != null) onSeek(details.seekTime);
+    });
+  }
+}
+
+/** Shows/hides the OS's own "next" control - called whenever this app's
+ *  own equivalent (Player.ts's #nextBtn, a queue advance in general)
+ *  would also change visibility. A *registered* handler is what makes
+ *  Windows show the button at all, regardless of whether clicking it
+ *  would currently do anything - so this has to track "is there
+ *  actually a next" the same way the in-page button does, not just be
+ *  set once and left there. */
+export function setMediaSessionNextAction(onNext: (() => void) | null): void {
+  if (!('mediaSession' in navigator)) return;
+  try {
+    navigator.mediaSession.setActionHandler('nexttrack', onNext);
+  } catch {
+    // An unrecognized action name on an older browser - safe to skip.
+  }
+}
+
+/** Drops the OS's own now-playing card without touching the play/pause/
+ *  seek handlers underneath it - for "still in the party, just nothing
+ *  queued right now" (MusicBar.ts's own `!music.current`), where those
+ *  handlers stay meaningful (playback can resume the moment a track
+ *  does) and so shouldn't need re-wiring the instant one does. `null`,
+ *  not an empty MediaMetadata - that's the documented way to tell the
+ *  OS there's genuinely nothing loaded, not a track with a blank title. */
+export function setMediaSessionIdle(): void {
+  if (!('mediaSession' in navigator)) return;
+  navigator.mediaSession.metadata = null;
+  navigator.mediaSession.playbackState = 'none';
+}
+
+/** Called when leaving a party/party page entirely - an OS-level "now
+ *  playing" card that outlives the actual party would be actively
+ *  wrong, not just stale, so this clears every piece the functions
+ *  above ever set (not just the now-playing card - see
+ *  setMediaSessionIdle above for that alone) rather than leaving it to
+ *  be silently overwritten by whatever starts next. */
+export function clearMediaSession(): void {
+  if (!('mediaSession' in navigator)) return;
+  setMediaSessionIdle();
+  try {
+    navigator.mediaSession.setActionHandler('play', null);
+    navigator.mediaSession.setActionHandler('pause', null);
+    navigator.mediaSession.setActionHandler('nexttrack', null);
+    navigator.mediaSession.setActionHandler('seekto', null);
+  } catch {
+    // Same tolerance as setMediaSessionNextAction above.
+  }
+}

client/src/musicBar/MusicBar.css

@@ -6,13 +6,14 @@
    able to browse/add tracks while it plays). Sits above .mainContent, at
    a lower z-index than .playerWrap (20) so a video party's takeover still
    correctly covers it - moot in practice since joining a video party
-   calls leaveMusicParty() first (see Player.ts), but cheap to get right. */
+   calls leaveMusicParty() first (see Player.ts), but cheap to get right.
+   The fixed-to-viewport positioning itself lives one level up, on
+   Shell.css's .bottomStack wrapper - not here - so that on a narrow
+   screen the mobile nav trigger right below it in that wrapper always
+   sits flush above this bar's own actual rendered height (its content
+   can wrap taller on a narrow screen), never a hardcoded guess at it. */
 .musicBar {
-  position: fixed;
-  left: 0;
-  right: 0;
-  bottom: 0;
-  z-index: 15;
+  position: relative; /* containing block for .musicBarQueue's own position: absolute - see its comment */
   background: var(--bg-header);
   border-top: 1px solid rgba(255, 255, 255, .08);
   box-shadow: 0 -4px 16px rgba(0, 0, 0, .3);
@@ -20,26 +21,139 @@
 
 /* A thin strip along the bar's own top edge, not inside .musicBarRow -
    the same "compact player" convention Spotify/YouTube Music use for
-   their mini-players. Read-only (see MusicBar.ts's own comment) - no
-   click/drag handling, just a visual position indicator. */
+   their mini-players. Click/drag to seek (see MusicBar.ts) - the
+   generous ::before hit-area below (not just the 3px visual track)
+   matters most for drag on a touch screen, same trick
+   views/player/Player.css's own .progressBar::before uses.
+   `position: relative` is what gives that absolutely-positioned
+   ::before something to size itself against.
+   `grid-column: 1 / -1` is the fix, not decoration: #trackProgress is
+   .musicBarPanel's first child, and without an explicit span a 3-column
+   grid places it in column 1 alone - squeezing it down to the width of
+   .musicBarPanelTrack's own column and wrapping .musicBarPanelSide onto
+   a second row underneath it, instead of the intended full-width strip
+   with everything else in one row below. Reported directly - never
+   looked obviously wrong at a glance since .musicBarPanelTrack's own
+   content (a small image + short text) left column 1 wide enough to
+   mostly hide the squeeze. Spanning this row is what pushes every
+   sibling after it into row 2, across all 3 columns, with no change
+   needed to them. */
 .musicBarProgressTrack {
+  grid-column: 1 / -1;
+  position: relative;
   height: 3px;
   background: rgba(255, 255, 255, .12);
+  cursor: pointer;
+  touch-action: none; /* this app's own pointer handlers drive the drag, not the browser's default touch scroll/zoom gestures */
+}
+
+.musicBarProgressTrack::before {
+  content: '';
+  position: absolute;
+  top: -8px;
+  bottom: -8px;
+  left: 0;
+  right: 0;
 }
 
 .musicBarProgressFill {
   height: 100%;
   width: 0%;
   background: var(--accent);
-  transition: width .25s linear;
+  pointer-events: none;
 }
 
-.musicBarRow {
+/* ---- Collapsed mobile preview (see MusicBar.html) - display:none by
+   default since #musicBarPanel below is already always visible on
+   desktop, nothing to collapse into a preview of there. Turned on
+   under the 720px breakpoint further down. ---- */
+.mobileMiniBar {
+  display: none;
+  align-items: center;
+  gap: 10px;
+  padding: 8px 12px;
+  position: relative;
+  cursor: pointer;
+}
+
+/* Passive - not draggable, unlike #trackProgress inside the panel below.
+   Glanceable progress while collapsed is enough; dragging is one tap
+   away once expanded, same as most real players' own mini-bar. */
+.mobileMiniProgress {
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  height: 2px;
+  background: rgba(255, 255, 255, .12);
+}
+
+.mobileMiniProgressFill {
+  height: 100%;
+  width: 0%;
+  background: var(--accent-bright);
+}
+
+.mobileMiniArt {
+  width: 36px;
+  height: 36px;
+  object-fit: cover;
+  border-radius: 6px;
+  background: var(--panel);
+  flex-shrink: 0;
+}
+
+.mobileMiniArt.noImage { visibility: hidden; }
+
+.mobileMiniMeta {
+  display: flex;
+  flex-direction: column;
+  gap: 1px;
+  min-width: 0;
+  flex: 1;
+}
+
+.mobileMiniMeta strong {
+  font-size: 13px;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+/* ---- The actual controls - always in place on desktop (this IS the
+   bar, same as before); a full-screen "now playing" overlay on mobile,
+   opened via #mobileMiniBar above and closed via #panelCloseBtn - see
+   the 720px breakpoint further down for the fixed-overlay/transform
+   part of this, unchanged here. ---- */
+.musicBarPanel {
+  display: grid;
+  grid-template-columns: 1fr auto 1fr;
+  align-items: center;
+  gap: 16px;
+  padding: 8px 16px;
+}
+
+.panelCloseBtn { display: none; }
+
+.musicBarPanelTrack {
   display: flex;
   align-items: center;
   gap: 12px;
-  padding: 8px 16px;
-  flex-wrap: wrap;
+  min-width: 0;
+}
+
+.musicBarPanelTransport {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 16px;
+}
+
+.musicBarPanelSide {
+  display: flex;
+  align-items: center;
+  justify-content: flex-end;
+  gap: 10px;
 }
 
 /* Smaller than the video player's presence row (Player.css/presence.css's
@@ -79,6 +193,60 @@
 
 .musicBarPosition { font-variant-numeric: tabular-nums; white-space: nowrap; }
 
+/* The one primary transport action, bigger and filled so it clearly
+   outranks the plain small .iconBtn (skip-vote/queue) either side of
+   it - same "obviously the main button" treatment
+   views/player/Player.ts's own controls already get, instead of
+   blending into a row of equally-weighted buttons. Shared between
+   #playPauseBtn (inside .musicBarPanel) and #miniPlayPauseBtn (the
+   collapsed mobile preview) - same look, same size, both wired to the
+   exact same toggle in MusicBar.ts. */
+/* .iconBtn.musicBarPlayBig, not just .musicBarPlayBig: both classes are
+   always present together on these two buttons (see MusicBar.html), so
+   this compound selector's higher specificity is what reliably beats
+   .iconBtn's own background/border-radius regardless of which of the
+   two files esbuild happens to bundle later - two plain single-class
+   selectors at equal specificity would otherwise depend on that bundle
+   order, which isn't something to build a visual guarantee on. */
+.iconBtn.musicBarPlayBig {
+  width: 34px;
+  height: 34px;
+  border-radius: 50%;
+  background: var(--text);
+  color: var(--bg);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0;
+  flex-shrink: 0;
+}
+
+.iconBtn.musicBarPlayBig:hover { background: var(--accent-bright); color: #fff; }
+.musicBarPlayBig svg { width: 14px; height: 14px; display: block; }
+
+/* #voteSkipBtn's own vote tally (see MusicBar.ts's updateVoteSkipLabel) -
+   a badge instead of the old "Passer (vote) - X/Y" text label, now that
+   the button itself is icon-only like every other transport control
+   here. Hidden (see MusicBar.html) until there's an actual tally to
+   show - matches every other conditionally-shown badge/pill elsewhere
+   in this app rather than showing "0/1" before anyone's voted. */
+#voteSkipBtn { position: relative; }
+
+.voteBadge {
+  position: absolute;
+  top: -4px;
+  right: -6px;
+  background: var(--accent);
+  color: #fff;
+  font-size: 9px;
+  font-weight: 700;
+  border-radius: 99px;
+  padding: 1px 4px;
+  min-width: 14px;
+  text-align: center;
+  line-height: 1.4;
+}
+
 /* #castBtn while actively casting - same "clearly-on" treatment as
    views/player/Player.css's own .iconBtn[aria-pressed="true"] (ID-scoped
    here rather than a shared .iconBtn rule since #playPauseBtn's own
@@ -91,14 +259,26 @@
 }
 
 /* Pops up ABOVE the bar (same pattern as Player.css's .settingsPanel above
-   its gear button) - collapsed by default, see MusicBar.ts's toggleQueueBtn
-   handler. Spans the full bar width (no max-width) rather than a fixed
-   popup box - a party's queue can run long, and a narrow column wastes
-   the width a desktop viewport already has going spare.
-   display:flex/flex-direction:column here (rather than on .pageHeader/
-   #queueList individually) is what lets #queueList be the only child
-   that scrolls below - see #queueList's own comment. */
+   its gear button - position: absolute against .musicBar's own
+   position: relative, bottom: 100% instead of that one's top: 100%/
+   right: 0, since this floats up from a bottom bar rather than down from
+   a top-corner icon) - collapsed by default, see MusicBar.ts's
+   toggleQueueBtn handler. `position: absolute` (not left in normal flow)
+   is what stops opening this from silently growing .bottomStack's own
+   fixed-to-viewport height and shoving the actual controls upward
+   instead of floating over them - reported directly as the desktop bar
+   looking broken the moment the queue was opened. Spans the full bar
+   width (no max-width) rather than a fixed popup box - a party's queue
+   can run long, and a narrow column wastes the width a desktop viewport
+   already has going spare. display:flex/flex-direction:column here
+   (rather than on .pageHeader/#queueList individually) is what lets
+   #queueList be the only child that scrolls below - see #queueList's own
+   comment. */
 .musicBarQueue {
+  position: absolute;
+  left: 0;
+  right: 0;
+  bottom: 100%;
   max-height: 50vh;
   margin: 0 16px;
   padding: 14px 14px 0;
@@ -112,6 +292,23 @@
 
 .musicBarQueue .pageHeader { flex-shrink: 0; }
 
+/* Always reachable regardless of z-index/positioning below (see
+   MusicBar.ts's own click-outside handler for the other way to close
+   this on desktop) - reported directly that, in mobile's full-screen
+   layout, the *only* previous way to close this (tap the same
+   #toggleQueueBtn again) sat visually underneath the now-open queue
+   panel itself once it covered the screen, making it unreachable. */
+.queueCloseBtn {
+  background: none;
+  color: var(--muted);
+  font-size: 12px;
+  font-weight: 400;
+  padding: 2px;
+  flex-shrink: 0;
+}
+
+.queueCloseBtn:hover { background: none; color: var(--text); }
+
 /* The only scrolling region inside .musicBarQueue - "File d'attente"
    above it stays put instead of scrolling away with the tracks. */
 #queueList {
@@ -119,9 +316,111 @@
 }
 
 @media (max-width: 720px) {
-  .musicBarRow { justify-content: center; }
-  .musicBarInfo { margin-right: 0; flex-basis: 100%; order: -1; text-align: center; }
-  .musicBarQueue { margin: 0; border-radius: 0; }
+  .mobileMiniBar { display: flex; }
+
+  /* Same fixed-overlay/slide-up-from-bottom pattern as Shell.css's
+     .mobileNavSheet - see docs/architecture.md's "Mobile navigation".
+     display stays flex unconditionally (not toggled) so the transform
+     transition below actually animates instead of jumping. */
+  .musicBarPanel {
+    position: fixed;
+    inset: 0;
+    z-index: 25;
+    display: flex;
+    flex-direction: column;
+    padding: 20px 20px calc(20px + env(safe-area-inset-bottom, 0px));
+    background: var(--bg);
+    transform: translateY(100%);
+    transition: transform .25s ease;
+    overflow-y: auto;
+  }
+
+  .musicBarPanel.open { transform: translateY(0); }
+
+  .panelCloseBtn {
+    display: flex;
+    color: var(--muted);
+    margin-bottom: 24px;
+  }
+
+  .musicBarPanelTrack {
+    flex-direction: column;
+    text-align: center;
+    margin-bottom: 24px;
+  }
+
+  .musicBarPanelTrack .musicBarImage {
+    width: min(220px, 60vw);
+    height: min(220px, 60vw);
+    border-radius: 12px;
+  }
+
+  .musicBarInfo { margin-right: 0; align-items: center; }
+  .musicBarInfo strong { font-size: 19px; white-space: normal; }
+  .musicBarPosition { margin-top: 6px; }
+
+  .musicBarPanelTransport { gap: 28px; margin-bottom: 28px; }
+  .musicBarPanelTransport .musicBarPlayBig { width: 56px; height: 56px; }
+  .musicBarPanelTransport .musicBarPlayBig svg { width: 22px; height: 22px; }
+
+  .musicBarPanelSide { margin-top: auto; justify-content: center; gap: 20px; }
+
+  /* A full-screen overlay of its own here, not desktop's floating popup
+     (there's no "above the bar" to float over once .musicBarPanel is
+     itself a full-screen overlay) - z-index: 26 (above .musicBarPanel's
+     25) is still what puts it on top, but `position: relative` used to
+     leave it in .musicBar's own normal flow, sized by `max-height: 50vh`
+     inherited from the base rule above and positioned whichever the
+     surrounding layout happened to allow - overlapping the very
+     #toggleQueueBtn used to open it, with no other way to close a
+     `position: relative` sibling that isn't just a small popup here.
+     `inset: 0` + `max-height: none` makes it genuinely full-screen like
+     .musicBarPanel itself, so its own #queueCloseBtn is always reachable
+     regardless of queue length. */
+  .musicBarQueue {
+    position: fixed;
+    inset: 0;
+    z-index: 26;
+    max-height: none;
+    margin: 0;
+    border-radius: 0;
+    padding: 20px 20px calc(20px + env(safe-area-inset-bottom, 0px));
+  }
+}
+
+/* Rotated: the block above stacks the art on top of everything else and
+   sizes it off the viewport's WIDTH (60vw) - reported directly as
+   overflowing/needing to scroll once width and height swap roles in
+   landscape, where width is the one dimension this screen never lacks.
+   Same fixed-overlay itself, just laid out differently - the art moves
+   beside the title/artist instead of above them (freeing most of the
+   vertical stack this screen otherwise spends on it), and every size
+   below is capped by `vh`, the scarce dimension here, not `vw`. Button
+   sizes are deliberately left alone (56px .musicBarPlayBig, the same
+   above) - a touch target sizes to a finger, not the screen, in any
+   orientation. */
+@media (max-width: 720px) and (orientation: landscape) {
+  .musicBarPanel {
+    padding-top: 10px;
+    padding-bottom: calc(10px + env(safe-area-inset-bottom, 0px));
+  }
+
+  .panelCloseBtn { margin-bottom: 6px; }
+
+  .musicBarPanelTrack {
+    flex-direction: row;
+    text-align: left;
+    margin-bottom: 8px;
+  }
+
+  .musicBarPanelTrack .musicBarImage {
+    width: min(120px, 20vh);
+    height: min(120px, 20vh);
+  }
+
+  .musicBarInfo { align-items: flex-start; }
+
+  .musicBarPanelTransport { margin-bottom: 8px; }
 }
 
 /* One queue entry - a plain flex row (image, then a shrinking/truncating

client/src/musicBar/MusicBar.html

@@ -1,26 +1,68 @@
 <div id="musicBarQueue" class="musicBarQueue hide">
   <div class="pageHeader">
     <h2>File d'attente</h2>
+    <button class="queueCloseBtn" id="queueCloseBtn" aria-label="Fermer la file d'attente">
+      <svg viewBox="0 0 24 24" width="20" height="20" aria-hidden="true">
+        <path d="M6 9l6 6 6-6" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"></path>
+      </svg>
+    </button>
   </div>
   <div id="queueList" class="trackList"><p class="hint">Rien en attente.</p></div>
 </div>
 
-<!-- Read-only - see MusicBar.ts's own comment on why this doesn't seek
-     (no host to arbitrate a jump, and MusicQueueService has no "seek"
-     concept server-side today - just play/pause/advance). -->
-<div id="trackProgress" class="musicBarProgressTrack"><div id="trackProgressFill" class="musicBarProgressFill"></div></div>
+<!-- Mobile-only collapsed preview (see MusicBar.css's 720px breakpoint) -
+     #musicBarPanel below is already always visible on desktop, so this
+     only ever renders there. Tapping anywhere on it except the play
+     button opens the panel - see MusicBar.ts. -->
+<div id="mobileMiniBar" class="mobileMiniBar">
+  <div class="mobileMiniProgress"><div id="miniProgressFill" class="mobileMiniProgressFill"></div></div>
+  <img id="miniTrackImage" class="mobileMiniArt" alt="" onerror="this.classList.add('noImage')" />
+  <div class="mobileMiniMeta">
+    <strong id="miniTrackName">-</strong>
+    <span class="hint" id="miniTrackArtist"></span>
+  </div>
+  <button class="iconBtn musicBarPlayBig" id="miniPlayPauseBtn" title="Lecture / pause" aria-label="Lecture / pause"></button>
+</div>
 
-<div class="musicBarRow">
-  <div id="presenceOverlay" class="presenceOverlay musicBarPresence"></div>
+<!-- Always in place on desktop (the bar itself, unconditionally visible
+     like before); a full-screen "now playing" overlay on mobile,
+     opened via #mobileMiniBar above and closed via #panelCloseBtn. -->
+<div id="musicBarPanel" class="musicBarPanel">
+  <button class="linklike panelCloseBtn" id="panelCloseBtn" aria-label="Réduire">
+    <svg viewBox="0 0 24 24" width="20" height="20" aria-hidden="true">
+      <path d="M6 9l6 6 6-6" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"></path>
+    </svg>
+  </button>
 
+  <!-- Click/drag to seek - see MusicBar.ts's pointerdown/move/up
+       handlers. No host check needed to enable this, unlike the video
+       player's own seek bar: a listen party has no host at all - see
+       MusicQueueService.seek's own comment for why that's the right
+       model for this, not voteSkip's majority gate. -->
+  <div id="trackProgress" class="musicBarProgressTrack"><div id="trackProgressFill" class="musicBarProgressFill"></div></div>
+
+  <div class="musicBarPanelTrack">
     <img id="trackImage" class="musicBarImage" alt="" onerror="this.classList.add('noImage')" />
     <div class="musicBarInfo">
       <strong id="trackName">-</strong>
       <span class="hint" id="trackArtist"></span>
     </div>
-
     <span id="trackPosition" class="hint musicBarPosition">0:00 / 0:00</span>
-  <button class="iconBtn" id="playPauseBtn" title="Lecture / pause" aria-label="Lecture / pause">&#9654;</button>
+  </div>
+
+  <div class="musicBarPanelTransport">
+    <button class="iconBtn" id="voteSkipBtn" title="Passer (vote)" aria-label="Passer (vote)">
+      <svg viewBox="0 0 24 24" width="16" height="16" aria-hidden="true"><path d="M5 5v14l10-7Z" fill="currentColor"></path><rect x="17" y="5" width="2.5" height="14" rx="1" fill="currentColor"></rect></svg>
+      <span id="voteBadge" class="voteBadge hide"></span>
+    </button>
+    <button class="iconBtn musicBarPlayBig" id="playPauseBtn" title="Lecture / pause" aria-label="Lecture / pause"></button>
+    <button class="iconBtn" id="toggleQueueBtn" title="File d'attente" aria-label="File d'attente">
+      <svg viewBox="0 0 24 24" width="16" height="16" aria-hidden="true"><circle cx="4.5" cy="7" r="1.3" fill="currentColor"></circle><circle cx="4.5" cy="12" r="1.3" fill="currentColor"></circle><circle cx="4.5" cy="17" r="1.3" fill="currentColor"></circle><line x1="9" y1="7" x2="20" y2="7" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"></line><line x1="9" y1="12" x2="20" y2="12" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"></line><line x1="9" y1="17" x2="20" y2="17" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"></line></svg>
+    </button>
+  </div>
+
+  <div class="musicBarPanelSide">
+    <div id="presenceOverlay" class="presenceOverlay musicBarPresence"></div>
     <button class="iconBtn hide" id="castBtn" title="Caster sur un Chromecast" aria-label="Caster sur un Chromecast" aria-pressed="false">
       <svg viewBox="0 0 24 24" width="16" height="16" aria-hidden="true">
         <rect x="1" y="4" width="22" height="16" rx="2" fill="none" stroke="currentColor" stroke-width="2"></rect>
@@ -29,8 +71,9 @@
         <circle cx="4" cy="20" r="1.5" fill="currentColor"></circle>
       </svg>
     </button>
-  <button class="linklike" id="voteSkipBtn">Passer (vote)</button>
-  <button class="linklike" id="toggleQueueBtn">File d'attente</button>
-  <button class="linklike" id="leaveBtn">Quitter</button>
+    <button class="iconBtn" id="leaveBtn" title="Quitter" aria-label="Quitter">
+      <svg viewBox="0 0 24 24" width="16" height="16" aria-hidden="true"><path d="M9 4.5H6a1.5 1.5 0 0 0-1.5 1.5v12A1.5 1.5 0 0 0 6 19.5h3" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"></path><path d="M13 8l4 4-4 4M9.5 12H20" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"></path></svg>
+    </button>
+  </div>
 </div>
 <audio id="barAudio"></audio>

client/src/musicBar/MusicBar.ts

@@ -6,9 +6,11 @@ import { partyStreamUrl } from '../api/embyApi';
 import { connectParty, issueCastToken, leaveParty, revokeCastToken } from '../api/party';
 import type { PartyConnection } from '../api/party';
 import { colorForName, escapeHtml, formatDuration, initialsFor } from '../tiles';
+import { showToast } from '../toast';
 import type { MusicCurrentPublic, MusicPublicState, PartyPublicState, SocketMember } from '../types';
 import { initCast, localDriver, onCastAvailabilityChanged, onCastSessionEnded, startCast, stopCast } from '../cast';
 import type { PlaybackDriver } from '../cast';
+import { clearMediaSession, setMediaSessionActionHandlers, setMediaSessionIdle, setMediaSessionMetadata, setMediaSessionNextAction, setMediaSessionPlaybackState, setMediaSessionPositionState } from '../mediaSession';
 
 /**
  * Persistent, app-lifetime "listen party" bar - mounted ONCE by Shell.ts
@@ -34,6 +36,12 @@ import type { PlaybackDriver } from '../cast';
  * for music parties.
  */
 
+// #playPauseBtn/#miniPlayPauseBtn's two states - real SVGs (not the old
+// '▶'/'⏸' text glyphs, which never matched Player.ts's own icon-button
+// convention used everywhere else this app shows a play/pause control).
+const PLAY_ICON_SVG = '<svg viewBox="0 0 24 24" aria-hidden="true"><path d="M6 4.5v15l14-7.5Z" fill="currentColor"></path></svg>';
+const PAUSE_ICON_SVG = '<svg viewBox="0 0 24 24" aria-hidden="true"><rect x="5" y="4" width="5" height="16" rx="1" fill="currentColor"></rect><rect x="14" y="4" width="5" height="16" rx="1" fill="currentColor"></rect></svg>';
+
 // See views/player/Player.ts's own HLS_CONFIG for why these are raised
 // well above hls.js's defaults (10s manifest/level/frag load timeouts) -
 // every track here also goes through CatalogService.proxyStream into a
@@ -94,21 +102,102 @@ export function initMusicBar(root: HTMLElement): void {
 
   const audio = barEl.querySelector('#barAudio') as HTMLAudioElement;
   const playPauseBtn = barEl.querySelector('#playPauseBtn') as HTMLButtonElement;
+  const miniPlayPauseBtn = barEl.querySelector('#miniPlayPauseBtn') as HTMLButtonElement;
   const castBtn = barEl.querySelector('#castBtn') as HTMLButtonElement;
   const voteSkipBtn = barEl.querySelector('#voteSkipBtn') as HTMLButtonElement;
   const toggleQueueBtn = barEl.querySelector('#toggleQueueBtn')!;
   const queuePanel = barEl.querySelector('#musicBarQueue')!;
+  const queueCloseBtn = barEl.querySelector('#queueCloseBtn')!;
   const leaveBtn = barEl.querySelector('#leaveBtn')!;
+  const trackProgress = barEl.querySelector('#trackProgress') as HTMLElement;
+  const mobileMiniBar = barEl.querySelector('#mobileMiniBar')!;
+  const musicBarPanel = barEl.querySelector('#musicBarPanel')!;
+  const panelCloseBtn = barEl.querySelector('#panelCloseBtn')!;
 
   activeDriver = localDriver(audio);
 
   audio.addEventListener('play', () => { if (!suppressLocalEvents && conn) conn.setMusicPaused(false); });
   audio.addEventListener('pause', () => { if (!suppressLocalEvents && conn) conn.setMusicPaused(true); });
   playPauseBtn.addEventListener('click', () => conn?.setMusicPaused(!activeDriver!.paused));
+  miniPlayPauseBtn.addEventListener('click', () => conn?.setMusicPaused(!activeDriver!.paused));
   voteSkipBtn.addEventListener('click', () => conn?.voteSkip());
   toggleQueueBtn.addEventListener('click', () => queuePanel.classList.toggle('hide'));
+  queueCloseBtn.addEventListener('click', () => queuePanel.classList.add('hide'));
+  // Desktop-popover convention (same as views/player/Player.ts's own
+  // settingsPanel) - closes on any click that lands neither inside the
+  // panel nor on the button that opens it. Harmless on mobile's
+  // full-screen layout too (there's no "outside" to click there, but
+  // #queueCloseBtn above is the real fix for that case - see
+  // MusicBar.css's own comment on why the old position: relative left
+  // that button unreachable once the queue was open).
+  document.addEventListener('click', (e) => {
+    if (queuePanel.classList.contains('hide')) return;
+    const target = e.target as Node;
+    if (!queuePanel.contains(target) && !toggleQueueBtn.contains(target)) {
+      queuePanel.classList.add('hide');
+    }
+  });
   leaveBtn.addEventListener('click', () => leaveMusicParty());
 
+  // Mobile only (see MusicBar.css's 720px breakpoint - .musicBarPanel is
+  // already always visible on desktop, so these two are simply never
+  // clicked/reachable there). The mini bar itself is the tap target
+  // (not just an icon on it) so there's a generous hit area on a touch
+  // screen - #miniPlayPauseBtn's own click above stops that one
+  // specific tap from also opening the panel via this listener.
+  mobileMiniBar.addEventListener('click', (e) => {
+    if ((e.target as HTMLElement).closest('#miniPlayPauseBtn')) return;
+    musicBarPanel.classList.add('open');
+  });
+  panelCloseBtn.addEventListener('click', () => musicBarPanel.classList.remove('open'));
+
+  // Click/drag to seek - no host check, unlike the video player's own
+  // seek bar, since a listen party has no host at all (see activeDriver's
+  // own comment) - anyone dragging this updates their own driver
+  // immediately (for instant visual feedback, same as the video player's
+  // own seekFromPointerEvent) and broadcasts it, same "anyone, straight
+  // away" treatment play/pause already has (see MusicQueueService.seek).
+  // Pointer events (not click/drag) so mouse and touch share one
+  // implementation, and setPointerCapture keeps the drag tracking even if
+  // the pointer leaves the track's own bounds mid-gesture - same pattern
+  // as Player.ts's progressBar.
+  let isDraggingProgress = false;
+
+  function seekTo(seconds: number): void {
+    if (currentDurationSeconds <= 0) return;
+    activeDriver!.currentTime = Math.min(Math.max(0, seconds), currentDurationSeconds);
+    updatePositionDisplay();
+    conn?.seekMusic(activeDriver!.currentTime);
+  }
+
+  function seekFromPointerEvent(e: PointerEvent): void {
+    if (currentDurationSeconds <= 0) return;
+    const rect = trackProgress.getBoundingClientRect();
+    const fraction = Math.min(1, Math.max(0, (e.clientX - rect.left) / rect.width));
+    seekTo(fraction * currentDurationSeconds);
+  }
+
+  trackProgress.addEventListener('pointerdown', (e) => {
+    isDraggingProgress = true;
+    trackProgress.setPointerCapture(e.pointerId);
+    seekFromPointerEvent(e);
+  });
+  trackProgress.addEventListener('pointermove', (e) => {
+    if (!isDraggingProgress) return;
+    seekFromPointerEvent(e);
+  });
+  trackProgress.addEventListener('pointerup', () => { isDraggingProgress = false; });
+  trackProgress.addEventListener('pointercancel', () => { isDraggingProgress = false; });
+
+  // Wired once, like Player.ts's own equivalent - no host concept here
+  // (see activeDriver's own comment) so, unlike there, play/pause never
+  // need to branch into a request-instead-of-act path.
+  setMediaSessionActionHandlers({
+    onPlay: () => conn?.setMusicPaused(false),
+    onPause: () => conn?.setMusicPaused(true),
+    onSeek: seekTo
+  });
+
   // Visible to any member the moment a Chromecast is on the network - not
   // gated on anything party-related, same as Player.ts's own castBtn
   // (see its comment: casting is available to any member, and this bar
@@ -126,15 +215,25 @@ export function initMusicBar(root: HTMLElement): void {
   // server updates, same "derive it client-side from a snapshot" approach
   // as Home's party-elapsed labels and the old MusicPlayer.ts - runs
   // continuously rather than only while a party is active (cheap: a
-  // no-op while !currentItemId).
-  positionTicker = window.setInterval(() => {
+  // no-op while !currentItemId). Also called directly right after a local
+  // seek (see seekFromPointerEvent above), for instant feedback instead
+  // of waiting up to 500ms for this same tick to catch up.
+  positionTicker = window.setInterval(updatePositionDisplay, 500);
+}
+
+function updatePositionDisplay(): void {
   if (!currentItemId) return;
   const currentTime = activeDriver!.currentTime;
   const position = barEl!.querySelector('#trackPosition')!;
   position.textContent = `${formatDuration(currentTime)} / ${formatDuration(currentDurationSeconds)}`;
-    const fill = barEl!.querySelector('#trackProgressFill') as HTMLElement;
-    fill.style.width = currentDurationSeconds > 0 ? `${Math.min(100, (currentTime / currentDurationSeconds) * 100)}%` : '0%';
-  }, 500);
+  const percent = currentDurationSeconds > 0 ? `${Math.min(100, (currentTime / currentDurationSeconds) * 100)}%` : '0%';
+  (barEl!.querySelector('#trackProgressFill') as HTMLElement).style.width = percent;
+  // Same passive indicator on the collapsed mobile preview - see
+  // MusicBar.css's .mobileMiniProgress. Kept a plain width sync rather
+  // than its own pointer-seek wiring: dragging is one tap (expand the
+  // panel) away, see #mobileMiniBar's own click handler.
+  (barEl!.querySelector('#miniProgressFill') as HTMLElement).style.width = percent;
+  setMediaSessionPositionState(currentDurationSeconds, currentTime);
 }
 
 /**
@@ -166,8 +265,25 @@ export function joinMusicParty(partyId: string, party: PartyPublicState): void {
       if (takeOver) conn?.confirmDeviceTakeover();
       else leaveMusicParty();
     },
-    onError: (message) => alert(message),
-    onClose: () => {}
+    onError: (message) => showToast(message, { variant: 'error' }),
+    // Fires for every disconnect, intentional or not - leaveMusicParty
+    // itself already clears activePartyId synchronously, well before its
+    // own conn.leave() actually closes the socket, so seeing it still set
+    // here means this device's connection died some other way (most
+    // often: replaced by a takeover on another device - see
+    // SocketGateway's "join" handler). Without this, the bar just sat
+    // there looking/sounding fully live forever on the old device, on a
+    // conn that was actually already dead underneath it - reported
+    // directly as "both devices end up on the session, controls never
+    // transfer." leaveMusicParty() is safe to call here even though the
+    // party already moved on: leaveParty's own deviceId check (see
+    // api/party.ts) makes its REST call a no-op for a stale device
+    // instead of ending the CURRENT device's membership by mistake.
+    onClose: () => {
+      if (!activePartyId) return;
+      showToast('Connexion à la party interrompue.', { variant: 'error' });
+      leaveMusicParty();
+    }
   });
 }
 
@@ -199,12 +315,14 @@ export function leaveMusicParty(): void {
   currentItemId = null;
   lastMusicState = null;
   latestMembers = [];
+  clearMediaSession();
 
   conn?.leave();
   conn = null;
 
   barEl!.classList.add('hide');
   barEl!.querySelector('#musicBarQueue')!.classList.add('hide');
+  barEl!.querySelector('#musicBarPanel')!.classList.remove('open');
 
   leaveParty(partyId).catch(() => {});
 }
@@ -238,11 +356,37 @@ async function castTrack(title: string): Promise<void> {
  *  pause listeners already do (see initMusicBar), since casting here has
  *  no host gate to check first (see activeDriver's own comment). */
 function onCastStateChanged(): void {
-  const playPauseBtn = barEl!.querySelector('#playPauseBtn') as HTMLButtonElement;
-  playPauseBtn.textContent = activeDriver!.paused ? '▶' : '⏸';
+  setPlayIcon(!activeDriver!.paused);
   if (!suppressLocalEvents) conn?.setMusicPaused(activeDriver!.paused);
 }
 
+/** Both play/pause buttons - the main one inside .musicBarPanel and the
+ *  collapsed mobile preview's own - always show the same state, so
+ *  every call site that used to touch just #playPauseBtn's textContent
+ *  updates both here instead of duplicating the innerHTML swap at each
+ *  one. */
+function setPlayIcon(isPlaying: boolean): void {
+  const icon = isPlaying ? PAUSE_ICON_SVG : PLAY_ICON_SVG;
+  (barEl!.querySelector('#playPauseBtn') as HTMLButtonElement).innerHTML = icon;
+  (barEl!.querySelector('#miniPlayPauseBtn') as HTMLButtonElement).innerHTML = icon;
+  setMediaSessionPlaybackState(isPlaying);
+}
+
+/** Same pairing as setPlayIcon above, for the track metadata shown in
+ *  both .musicBarPanel and the collapsed mobile preview. */
+function setTrackMeta(imageUrl: string, name: string, artist: string): void {
+  const trackImage = barEl!.querySelector('#trackImage') as HTMLImageElement;
+  const miniTrackImage = barEl!.querySelector('#miniTrackImage') as HTMLImageElement;
+  trackImage.src = imageUrl;
+  trackImage.classList.remove('noImage');
+  miniTrackImage.src = imageUrl;
+  miniTrackImage.classList.remove('noImage');
+  barEl!.querySelector('#trackName')!.textContent = name;
+  barEl!.querySelector('#miniTrackName')!.textContent = name;
+  barEl!.querySelector('#trackArtist')!.textContent = artist;
+  barEl!.querySelector('#miniTrackArtist')!.textContent = artist;
+}
+
 /**
  * Starts casting - available to any listener, not just... there is no
  * "just", a listen party has no host (see activeDriver's own comment).
@@ -316,16 +460,13 @@ function endCastAndResync(): void {
  * (isCasting) delegated to castTrack/loadTrackLocal below.
  */
 function loadTrack(track: MusicCurrentPublic, elapsedSeconds: number, isPaused: boolean): void {
-  const trackImage = barEl!.querySelector('#trackImage') as HTMLImageElement;
-  const trackName = barEl!.querySelector('#trackName')!;
-  const trackArtist = barEl!.querySelector('#trackArtist')!;
-
   currentItemId = track.itemId;
   currentDurationSeconds = track.durationSeconds || 0;
-  trackImage.src = track.itemImageUrl || '';
-  trackImage.classList.remove('noImage');
-  trackName.textContent = track.itemName || '';
-  trackArtist.textContent = [track.artistName, track.albumName].filter(Boolean).join(' - ');
+  setTrackMeta(track.itemImageUrl || '', track.itemName || '', [track.artistName, track.albumName].filter(Boolean).join(' - '));
+  // Artist/album kept separate here, unlike setTrackMeta's own combined
+  // display line above - the OS's own now-playing UI has real fields for
+  // both, no need to pre-join them into one string for it.
+  setMediaSessionMetadata(track.itemName || '', track.artistName || '', track.albumName || '', track.itemImageUrl || '');
 
   if (isCasting) {
     castTrack([track.itemName, track.artistName].filter(Boolean).join(' - ')).catch((err) => {
@@ -403,37 +544,43 @@ function loadTrackLocal(track: MusicCurrentPublic, elapsedSeconds: number, isPau
  */
 function updateVoteSkipLabel(): void {
   const voteSkipBtn = barEl!.querySelector('#voteSkipBtn') as HTMLButtonElement;
+  const voteBadge = barEl!.querySelector('#voteBadge') as HTMLElement;
   const current = lastMusicState?.current;
   voteSkipBtn.disabled = !current;
   if (!current) {
-    voteSkipBtn.textContent = 'Passer (vote)';
+    voteBadge.classList.add('hide');
     return;
   }
   const connectedCount = latestMembers.filter((m) => m.connected).length || 1;
   const needed = Math.floor(connectedCount / 2) + 1;
-  voteSkipBtn.textContent = `Passer (vote) - ${lastMusicState!.skipVotes}/${needed}`;
+  voteBadge.textContent = `${lastMusicState!.skipVotes}/${needed}`;
+  voteBadge.classList.remove('hide');
 }
 
 function applyMusicState(music: MusicPublicState): void {
   lastMusicState = music;
 
   const playPauseBtn = barEl!.querySelector('#playPauseBtn') as HTMLButtonElement;
+  const miniPlayPauseBtn = barEl!.querySelector('#miniPlayPauseBtn') as HTMLButtonElement;
   const castBtn = barEl!.querySelector('#castBtn') as HTMLButtonElement;
   const queueList = barEl!.querySelector('#queueList')!;
-  const trackName = barEl!.querySelector('#trackName')!;
-  const trackArtist = barEl!.querySelector('#trackArtist')!;
-  const trackImage = barEl!.querySelector('#trackImage') as HTMLImageElement;
   const audio = barEl!.querySelector('#barAudio') as HTMLAudioElement;
 
   // Queue/vote-button/play-icon updates happen first, unconditionally,
   // deliberately BEFORE the track-loading branch below (see loadTrack's
   // own comment on why - same ordering as Player.ts/the old MusicPlayer.ts).
-  playPauseBtn.textContent = music.current && !music.current.isPaused ? '⏸' : '▶';
+  setPlayIcon(Boolean(music.current && !music.current.isPaused));
   playPauseBtn.disabled = !music.current;
+  miniPlayPauseBtn.disabled = !music.current;
   // Nothing for startCasting to actually cast with an empty queue - same
   // "disable, don't just silently no-op" treatment as playPauseBtn above.
   castBtn.disabled = !music.current && !isCasting;
   updateVoteSkipLabel();
+  // A *registered* nexttrack handler is what makes the OS show the
+  // control at all (see setMediaSessionNextAction's own comment) - same
+  // "disable, don't just silently no-op" case as playPauseBtn/castBtn
+  // above, just with no disabled state of its own to set instead.
+  setMediaSessionNextAction(music.current ? () => conn?.voteSkip() : null);
 
   // Its own .queueRow, NOT views/album's shared .trackRow (see
   // styles/trackList.css) - that one is a CSS grid whose 4 columns
@@ -456,13 +603,13 @@ function applyMusicState(music: MusicPublicState): void {
 
   if (!music.current) {
     currentItemId = null;
-    trackName.textContent = 'Rien ne joue pour le moment.';
-    trackArtist.textContent = '';
-    trackImage.src = '';
+    setTrackMeta('', 'Rien ne joue pour le moment.', '');
+    setMediaSessionIdle();
     if (hls) { hls.destroy(); hls = null; }
     activeDriver!.pause();
     audio.removeAttribute('src'); // harmless no-op while casting - the local element is already srcless then, see startCasting
     (barEl!.querySelector('#trackProgressFill') as HTMLElement).style.width = '0%';
+    (barEl!.querySelector('#miniProgressFill') as HTMLElement).style.width = '0%';
   } else if (music.current.itemId !== currentItemId) {
     loadTrack(music.current, music.current.elapsedSeconds, music.current.isPaused);
   } else {

client/src/public/manifest.webmanifest

@@ -0,0 +1,16 @@
+{
+  "name": "Watch Party",
+  "short_name": "Watch Party",
+  "description": "Regardez et écoutez en même temps que les autres utilisateurs de votre serveur Emby.",
+  "lang": "fr",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#151216",
+  "theme_color": "#221d24",
+  "categories": ["entertainment", "multimedia"],
+  "icons": [
+    { "src": "icons/icon-192.png", "sizes": "192x192", "type": "image/png", "purpose": "any" },
+    { "src": "icons/icon-512.png", "sizes": "512x512", "type": "image/png", "purpose": "any" },
+    { "src": "icons/icon-512-maskable.png", "sizes": "512x512", "type": "image/png", "purpose": "maskable" }
+  ]
+}

client/src/pwaInstall.css

@@ -0,0 +1,46 @@
+/* ---- Mobile-only "install this as an app" banner - see pwaInstall.ts.
+   A normal-flow element at the very top of <body>, before #app, not a
+   fixed/sticky overlay - pushes the app down by its own height instead
+   of needing to coordinate an offset with shell/Shell.css's own
+   .mobileTopBar/.libraryHeader (already stacked on top of each other at
+   the same breakpoint) or alphaIndex.css's rail. Scrolls away with the
+   page like any other content above the sticky chrome, same as a
+   browser's own native install infobar would. ---- */
+.pwaInstallBanner {
+  display: none;
+  align-items: center;
+  gap: 10px;
+  padding: 10px 14px;
+  background: var(--accent);
+  color: #fff;
+  font-size: 13px;
+  line-height: 1.35;
+}
+
+.pwaInstallText { flex: 1; min-width: 0; }
+
+.pwaInstallBtn {
+  flex-shrink: 0;
+  background: #fff;
+  color: var(--accent);
+  font-size: 12px;
+  font-weight: 700;
+  padding: 6px 12px;
+}
+
+.pwaInstallBtn:hover { background: rgba(255, 255, 255, .85); }
+
+.pwaInstallClose {
+  flex-shrink: 0;
+  background: none;
+  color: #fff;
+  font-size: 20px;
+  line-height: 1;
+  padding: 0 2px;
+}
+
+.pwaInstallClose:hover { background: none; opacity: .8; }
+
+@media (max-width: 720px) {
+  .pwaInstallBanner { display: flex; }
+}

client/src/pwaInstall.ts

@@ -0,0 +1,108 @@
+// Mobile-only "install this as an app" nudge - see docs/architecture.md.
+// Self-mounting like toast.ts (no per-route/per-party state to attach),
+// but the beforeinstallprompt listener below is attached the moment
+// this module is first imported - app.ts does that at the very top,
+// well before boot()'s async login check - rather than lazily on first
+// use like toast.ts: the browser only ever fires this event once per
+// page load, often before any UI exists to react to it, and there's no
+// way to ask for a replay if a listener attaches too late to catch it.
+import './pwaInstall.css';
+
+/** Chrome/Edge/Android-WebView's own install-prompt event - not in
+ *  lib.dom.d.ts (Safari/Firefox never implement it at all). */
+interface BeforeInstallPromptEvent extends Event {
+  prompt(): Promise<void>;
+  userChoice: Promise<{ outcome: 'accepted' | 'dismissed' }>;
+}
+
+const DISMISSED_KEY = 'watchparty:pwaInstallDismissed';
+const MOBILE_QUERY = '(max-width: 720px)';
+
+let deferredPrompt: BeforeInstallPromptEvent | null = null;
+let bannerEl: HTMLElement | null = null;
+
+window.addEventListener('beforeinstallprompt', (e) => {
+  e.preventDefault(); // suppress the browser's own mini-infobar - this banner replaces it
+  deferredPrompt = e as BeforeInstallPromptEvent;
+  renderIfEligible();
+});
+
+window.addEventListener('appinstalled', () => {
+  deferredPrompt = null;
+  removeBanner();
+});
+
+function isStandalone(): boolean {
+  return window.matchMedia('(display-mode: standalone)').matches
+    || (navigator as unknown as { standalone?: boolean }).standalone === true; // iOS Safari's own flag - no display-mode query there
+}
+
+/** No feature-detection exists for "is this iOS Safari" - beforeinstallprompt
+ *  simply never fires there, which is the actual fact this module cares
+ *  about, but by the time that's observable it's too late to show
+ *  install instructions instead. Checked only as a fallback once
+ *  deferredPrompt has had a real chance to arrive - see renderIfEligible. */
+function isIOS(): boolean {
+  return /iphone|ipad|ipod/i.test(navigator.userAgent)
+    || (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1); // iPadOS 13+ reports as a Mac
+}
+
+function removeBanner(): void {
+  bannerEl?.remove();
+  bannerEl = null;
+}
+
+function dismiss(): void {
+  localStorage.setItem(DISMISSED_KEY, '1');
+  removeBanner();
+}
+
+async function install(): Promise<void> {
+  if (!deferredPrompt) return;
+  const prompt = deferredPrompt;
+  deferredPrompt = null; // a captured prompt can only ever be used once
+  await prompt.prompt();
+  const { outcome } = await prompt.userChoice;
+  // 'dismissed' here means the user closed the browser's own native
+  // picker without installing - not the same signal as our own close
+  // button (dismiss() above), so this banner stays up rather than
+  // remembering "never ask again" over a single not-right-now.
+  if (outcome === 'accepted') removeBanner();
+}
+
+function renderIfEligible(): void {
+  if (bannerEl) return;
+  if (isStandalone()) return;
+  if (localStorage.getItem(DISMISSED_KEY)) return;
+  if (!window.matchMedia(MOBILE_QUERY).matches) return;
+
+  const ios = isIOS();
+  if (!deferredPrompt && !ios) return; // no install path this module actually knows how to help with
+
+  bannerEl = document.createElement('div');
+  bannerEl.className = 'pwaInstallBanner';
+  bannerEl.innerHTML = ios
+    ? `<span class="pwaInstallText">Installe Watch Party : appuie sur <strong>Partager</strong> puis « Sur l'écran d'accueil ».</span>
+       <button type="button" class="pwaInstallClose" aria-label="Fermer">&times;</button>`
+    : `<span class="pwaInstallText">Installe Watch Party sur ton écran d'accueil pour y accéder plus vite.</span>
+       <button type="button" class="pwaInstallBtn">Installer</button>
+       <button type="button" class="pwaInstallClose" aria-label="Fermer">&times;</button>`;
+
+  bannerEl.querySelector('.pwaInstallClose')!.addEventListener('click', dismiss);
+  bannerEl.querySelector('.pwaInstallBtn')?.addEventListener('click', () => { install().catch(() => {}); });
+
+  document.body.insertBefore(bannerEl, document.body.firstChild);
+}
+
+/**
+ * Called once by Shell.ts after a successful login - covers both the
+ * case where beforeinstallprompt already fired before Shell existed to
+ * react to it (deferredPrompt sitting ready, banner never actually
+ * shown yet) and iOS, which has no event at all to trigger this from.
+ * Also re-checked on resize: crossing the 720px breakpoint live (an
+ * unfolding or rotated device) shouldn't need a reload to notice.
+ */
+export function initPwaInstallPrompt(): void {
+  renderIfEligible();
+  window.addEventListener('resize', renderIfEligible);
+}

client/src/shell/Shell.css

@@ -62,20 +62,190 @@
   padding: 24px clamp(16px, 3vw, 48px) 80px;
 }
 
-/* Sidebar becomes a horizontal scrollable topbar on narrow screens. */
+/* ==== Mobile navigation (<=720px) ====
+   Replaces the sidebar outright - see docs/architecture.md's "Mobile
+   navigation" section for why a bottom sheet was chosen over reshaping
+   the sidebar into a horizontal bar. Every rule below the base
+   `display: none` only ever applies once the 720px media query turns
+   it back on, so none of this affects desktop. */
+.mobileTopBar,
+.mobileNavTrigger,
+.mobileNavScrim,
+.mobileNavSheet {
+  display: none;
+}
+
+.mobileTopBar {
+  position: sticky;
+  top: 0;
+  z-index: 3;
+  height: var(--mobile-topbar-h);
+  padding: 0 16px;
+  background: var(--bg-header);
+}
+
+.mobileBrand { font-size: 16px; font-weight: 700; }
+
+/* position:fixed, not sticky - #musicBar below already relies on a
+   fixed wrapper to stay docked regardless of how far #mainContent's
+   own (whole-page, not internally-scrolled) content runs. */
+.bottomStack {
+  position: fixed;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  z-index: 15;
+  display: flex;
+  flex-direction: column;
+}
+
+.mobileNavTrigger {
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  background: var(--bg-header);
+  border: none;
+  border-top: 1px solid rgba(255, 255, 255, .08);
+  color: var(--text);
+  font-family: inherit;
+  font-size: 13px;
+  font-weight: 600;
+  padding: 13px;
+  padding-bottom: calc(13px + env(safe-area-inset-bottom, 0px));
+}
+
+.mobileNavScrim {
+  position: fixed;
+  inset: 0;
+  z-index: 20;
+  background: rgba(0, 0, 0, .5);
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity .2s;
+  /* A touch starting here has no scrollable content of its own to
+     "contain" (overscroll-behavior wouldn't apply) - this is what
+     stops the browser reading a drag over the dimmed backdrop as a
+     page-level gesture (pull-to-refresh) instead of just dismissing
+     the sheet via the existing tap-to-close below. */
+  touch-action: none;
+}
+
+.mobileNavScrim.open { opacity: 1; pointer-events: auto; }
+
+.mobileNavSheet {
+  position: fixed;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  z-index: 21;
+  max-height: 75vh;
+  overflow-y: auto;
+  /* Stops a drag that hits the top of the sheet's OWN scroll (its
+     library grid can be taller than 75vh) from chaining past this
+     element to the page underneath and surfacing as pull-to-refresh -
+     complements touch-action:none on the dedicated grabber handle
+     below, which instead covers a drag that never scrolls anything. */
+  overscroll-behavior: contain;
+  background: var(--bg-header);
+  border-radius: 16px 16px 0 0;
+  padding: 8px 16px calc(20px + env(safe-area-inset-bottom, 0px));
+  transform: translateY(100%);
+  transition: transform .22s ease;
+  box-shadow: 0 -8px 24px rgba(0, 0, 0, .3);
+}
+
+.mobileNavSheet.open { transform: translateY(0); }
+
+/* Dragging (see Shell.ts) suspends the transition above for 1:1
+   tracking under the finger, then this class restores it for the
+   snap-back/close animation - same "instant while dragging, animated
+   on release" split views/player/Player.css's own seek bar uses. */
+.mobileNavSheet.dragging { transition: none; }
+
+/* Bigger drag/touch target than the pill it contains (36x4px is far
+   below a real touch-target minimum) - see Shell.html/Shell.ts. */
+.sheetGrabberHandle {
+  display: flex;
+  justify-content: center;
+  padding: 14px 0 10px;
+  touch-action: none;
+  cursor: grab;
+}
+
+.sheetGrabber {
+  width: 36px;
+  height: 4px;
+  border-radius: 99px;
+  background: var(--muted);
+}
+
+/* Accueil and the (conditional) Listes de lecture row both use this -
+   same visual weight, bookending the "Bibliothèques" group between
+   them, so the one part whose size actually varies (however many
+   libraries Emby returns) reads as visually distinct from the two
+   fixed rows around it. */
+.sheetPrimary {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  width: 100%;
+  background: var(--panel);
+  border: none;
+  border-radius: 10px;
+  color: var(--text);
+  font-family: inherit;
+  font-size: 14px;
+  font-weight: 600;
+  padding: 12px;
+  margin: 4px 0;
+  text-decoration: none;
+}
+
+.sheetPrimary.active { background: var(--accent); color: #fff; }
+
+.sheetGrid {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 8px;
+  margin: 4px 0 10px;
+}
+
+.sheetItem {
+  display: flex;
+  align-items: center;
+  gap: 9px;
+  background: var(--panel);
+  border-radius: 10px;
+  color: var(--text);
+  font-size: 13px;
+  padding: 12px 10px;
+  text-decoration: none;
+}
+
+.sheetItem.active { background: var(--accent); color: #fff; font-weight: 600; }
+
+.navIcon { width: 20px; height: 20px; flex-shrink: 0; display: block; }
+.navIcon svg { width: 100%; height: 100%; }
+
+.sheetLogout {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  width: 100%;
+  margin-top: 8px;
+  padding: 12px;
+  border: 1px solid rgba(255, 255, 255, .15);
+  border-radius: 10px;
+  color: var(--muted);
+  font-size: 13px;
+}
+
 @media (max-width: 720px) {
   .appShell { flex-direction: column; }
-  .sidebar {
-    width: 100%;
-    height: auto;
-    flex-direction: row;
-    align-items: center;
-    padding: 10px 12px;
-    overflow-x: auto;
-    overflow-y: hidden;
-  }
-  .sidebarBrand { padding: 0 12px 0 0; }
-  .sidebarNav { flex-direction: row; flex: none; }
-  .navSectionLabel { display: none; }
-  .sidebarLogout { margin: 0 0 0 12px; }
+  .sidebar { display: none; }
+  .mobileTopBar { display: flex; align-items: center; }
+  .mobileNavTrigger { display: flex; }
+  .mobileNavScrim { display: block; }
+  .mobileNavSheet { display: block; }
 }

client/src/shell/Shell.html

@@ -3,11 +3,49 @@
     <div class="sidebarBrand">Watch Party</div>
     <nav class="sidebarNav" id="sidebarNav">
       <a href="#/home" class="navItem">Accueil</a>
+      <a href="#/static" class="navItem">Lounge parties</a>
       <div class="navSectionLabel">Bibliothèques</div>
       <p class="hint" id="libStatus"><span class="spinner"></span>Chargement...</p>
     </nav>
-    <button class="linklike sidebarLogout" id="logout"></button>
+    <button class="linklike sidebarLogout logoutBtn" id="logout"></button>
   </aside>
+
+  <!-- Mobile-only (see Shell.css's 720px breakpoint) - the sidebar
+       above is display:none there instead of reshaping into a
+       horizontal bar. See docs/architecture.md's "Mobile navigation". -->
+  <header class="mobileTopBar">
+    <span class="mobileBrand">Watch Party</span>
+  </header>
+
   <main id="mainContent" class="mainContent"></main>
+
+  <!-- Wraps #musicBar so the trigger below always sits directly above
+       whatever height the bar actually renders at - see Shell.css. -->
+  <div class="bottomStack">
     <div id="musicBar" class="musicBar"></div>
+    <button class="mobileNavTrigger" id="mobileNavTrigger" aria-expanded="false" aria-controls="mobileNavSheet">
+      Parcourir
+      <svg viewBox="0 0 24 24" width="14" height="14" aria-hidden="true">
+        <path d="M6 9l6 6 6-6" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"></path>
+      </svg>
+    </button>
+  </div>
+
+  <div class="mobileNavScrim" id="mobileNavScrim"></div>
+  <div class="mobileNavSheet" id="mobileNavSheet">
+    <!-- Bigger invisible drag target than the visible pill itself (see
+         .sheetGrabberHandle) - touch-action:none so this app's own
+         pointer handlers (Shell.ts) drive the drag instead of the
+         browser's default touch handling, which otherwise reads a
+         downward drag here as pull-to-refresh (the sheet sits right at
+         the top of the page's own scroll position, same conflict a
+         plain scrim tap-only close used to leave unsolved). -->
+    <div class="sheetGrabberHandle" id="sheetGrabberHandle"><div class="sheetGrabber"></div></div>
+    <a href="#/home" class="navItem sheetPrimary"><span class="navIcon" data-icon="home"></span>Accueil</a>
+    <a href="#/static" class="navItem sheetPrimary"><span class="navIcon" data-icon="static"></span>Lounge parties</a>
+    <div class="navSectionLabel">Bibliothèques</div>
+    <div class="sheetGrid" id="mobileLibGrid"></div>
+    <div id="mobilePlaylistsSlot"></div>
+    <button class="linklike sheetLogout logoutBtn" id="mobileLogout"></button>
+  </div>
 </div>

client/src/shell/Shell.ts

@@ -5,47 +5,169 @@ import './Shell.css';
 import html from './Shell.html';
 import { auth, getLibraries, logout } from '../api/embyApi';
 import { initMusicBar } from '../musicBar/MusicBar';
+import { initPwaInstallPrompt } from '../pwaInstall';
+import type { LibraryDto } from '../types';
+
+// One icon per Emby CollectionType - only used by the mobile bottom
+// sheet (see docs/architecture.md's "Mobile navigation"); the desktop
+// sidebar stays plain text, unchanged. Same small inline-SVG-constant
+// convention as views/player/Player.ts's own icon strings.
+const HOME_ICON_SVG = '<svg viewBox="0 0 24 24"><path d="M3.5 11.5 12 4l8.5 7.5" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"/><path d="M5.5 10v9a1 1 0 0 0 1 1H10v-5.5a1 1 0 0 1 1-1h2a1 1 0 0 1 1 1V20h3.5a1 1 0 0 0 1-1v-9" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"/></svg>';
+const MOVIES_ICON_SVG = '<svg viewBox="0 0 24 24"><rect x="3.5" y="6" width="17" height="13" rx="1.5" fill="none" stroke="currentColor" stroke-width="1.8"/><path d="M3.5 6 7 3h3l-2.5 3M11 6l2.5-3h3L14 6m3.5 0 2.5-3" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"/></svg>';
+const SHOWS_ICON_SVG = '<svg viewBox="0 0 24 24"><rect x="3" y="5.5" width="18" height="12" rx="1.5" fill="none" stroke="currentColor" stroke-width="1.8"/><path d="M9 20.5h6M12 17.5v3" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"/></svg>';
+const MUSIC_ICON_SVG = '<svg viewBox="0 0 24 24"><circle cx="8" cy="17" r="2.6" fill="none" stroke="currentColor" stroke-width="1.8"/><path d="M10.5 17V5.5l7-1.5v10" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"/><circle cx="17.5" cy="14" r="2.6" fill="none" stroke="currentColor" stroke-width="1.8"/></svg>';
+const MUSICVIDEOS_ICON_SVG = '<svg viewBox="0 0 24 24"><rect x="3" y="5.5" width="18" height="13" rx="1.5" fill="none" stroke="currentColor" stroke-width="1.8"/><path d="M10 9.5 15.5 12 10 14.5Z" fill="currentColor"/></svg>';
+const PLAYLISTS_ICON_SVG = '<svg viewBox="0 0 24 24"><circle cx="4.5" cy="7" r="1.3" fill="currentColor"/><circle cx="4.5" cy="12" r="1.3" fill="currentColor"/><circle cx="4.5" cy="17" r="1.3" fill="currentColor"/><line x1="9" y1="7" x2="20" y2="7" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"/><line x1="9" y1="12" x2="20" y2="12" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"/><line x1="9" y1="17" x2="20" y2="17" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"/></svg>';
+// The "Lounge parties" tab (static watch parties) - a circular "resume" arrow.
+const STATIC_PARTIES_ICON_SVG = '<svg viewBox="0 0 24 24"><path d="M19.5 12a7.5 7.5 0 1 1-2.2-5.3" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"/><path d="M19.5 4v4h-4" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"/><path d="M10 9l5 3-5 3Z" fill="currentColor"/></svg>';
+// Emby could in principle add a CollectionType this app doesn't map yet
+// (server/src/services/CatalogService.ts's VISIBLE_COLLECTION_TYPES
+// would need updating first either way) - falls back to a plain folder
+// glyph rather than rendering an empty icon slot.
+const GENERIC_LIBRARY_ICON_SVG = '<svg viewBox="0 0 24 24"><rect x="3.5" y="5" width="17" height="14" rx="2" fill="none" stroke="currentColor" stroke-width="1.8"/></svg>';
+
+const COLLECTION_ICONS: Record<string, string> = {
+  movies: MOVIES_ICON_SVG,
+  tvshows: SHOWS_ICON_SVG,
+  music: MUSIC_ICON_SVG,
+  musicvideos: MUSICVIDEOS_ICON_SVG,
+  playlists: PLAYLISTS_ICON_SVG,
+};
+
+/** One `<a>` per library, shared by the desktop sidebar (plain text)
+ *  and the mobile sheet (icon + text) - `withIcon` is the only
+ *  difference between the two call sites below. */
+function createLibraryLink(lib: LibraryDto, className: string, withIcon: boolean): HTMLAnchorElement {
+  const a = document.createElement('a');
+  a.href = `#/library/${lib.id}`;
+  a.className = className;
+  if (withIcon) {
+    const icon = document.createElement('span');
+    icon.className = 'navIcon';
+    icon.innerHTML = COLLECTION_ICONS[lib.collectionType] || GENERIC_LIBRARY_ICON_SVG;
+    a.appendChild(icon);
+  }
+  a.appendChild(document.createTextNode(lib.name));
+  return a;
+}
 
 export async function renderShell(appEl: HTMLElement): Promise<HTMLElement> {
   appEl.innerHTML = html;
-  appEl.querySelector('#logout')!.textContent = `Se déconnecter (${auth.userName || ''})`;
+
+  appEl.querySelector('[data-icon="home"]')!.innerHTML = HOME_ICON_SVG;
+  appEl.querySelector('[data-icon="static"]')!.innerHTML = STATIC_PARTIES_ICON_SVG;
 
   // Mounted once, outside #mainContent, so a listen party survives
   // navigating the router - see musicBar/MusicBar.ts's header comment.
   initMusicBar(appEl.querySelector('#musicBar') as HTMLElement);
+  initPwaInstallPrompt();
 
-  appEl.querySelector('#logout')!.addEventListener('click', async () => {
+  // Both the sidebar's and the mobile sheet's logout button - same
+  // label, same handler, one line each instead of a shared DOM node
+  // fought over by two very differently-laid-out containers.
+  appEl.querySelectorAll<HTMLButtonElement>('.logoutBtn').forEach((btn) => {
+    btn.textContent = `Se déconnecter (${auth.userName || ''})`;
+    btn.addEventListener('click', async () => {
       await logout();
       // Simplest reliable way back to a bare login screen: a real reload,
       // rather than hand-tearing-down every shell/router listener in place.
       location.hash = '';
       location.reload();
     });
+  });
 
   const nav = appEl.querySelector('#sidebarNav')!;
   const status = appEl.querySelector('#libStatus')!;
+  const mobileLibGrid = appEl.querySelector('#mobileLibGrid')!;
+  const mobilePlaylistsSlot = appEl.querySelector('#mobilePlaylistsSlot')!;
   try {
     const libraries = await getLibraries();
     status.remove();
     libraries.forEach((lib) => {
-      const a = document.createElement('a');
-      a.href = `#/library/${lib.id}`;
-      a.className = 'navItem';
-      a.textContent = lib.name;
-      nav.appendChild(a);
+      nav.appendChild(createLibraryLink(lib, 'navItem', false));
+      // 'playlists' gets pulled out of the "Bibliothèques" group into
+      // its own fixed row - see docs/architecture.md. Everything else
+      // (movies/tvshows/music/musicvideos, whatever mix this server
+      // actually has) lands in the grid, unchanged in count or order.
+      if (lib.collectionType === 'playlists') {
+        mobilePlaylistsSlot.appendChild(createLibraryLink(lib, 'navItem sheetPrimary', true));
+      } else {
+        mobileLibGrid.appendChild(createLibraryLink(lib, 'navItem sheetItem', true));
+      }
     });
   } catch {
     status.textContent = 'Bibliothèques indisponibles.';
   }
 
   const highlight = () => {
-    nav.querySelectorAll('.navItem').forEach((a) => {
-      const isHome = a.getAttribute('href') === '#/home';
-      a.classList.toggle('active', a.getAttribute('href') === location.hash || (isHome && !location.hash));
+    appEl.querySelectorAll('.navItem').forEach((a) => {
+      const href = a.getAttribute('href');
+      const isHome = href === '#/home';
+      // The static-parties tab stays highlighted on one party's own page too.
+      const isStaticSection = href === '#/static' && location.hash.startsWith('#/static/');
+      a.classList.toggle('active', href === location.hash || (isHome && !location.hash) || isStaticSection);
     });
   };
   highlight();
   window.addEventListener('hashchange', highlight);
 
+  // ---- Mobile bottom sheet - see Shell.css's "Mobile navigation". ----
+  const navTrigger = appEl.querySelector('#mobileNavTrigger') as HTMLButtonElement;
+  const navSheet = appEl.querySelector('#mobileNavSheet') as HTMLElement;
+  const navScrim = appEl.querySelector('#mobileNavScrim')!;
+  const closeMobileNav = () => {
+    navSheet.classList.remove('open');
+    navScrim.classList.remove('open');
+    navTrigger.setAttribute('aria-expanded', 'false');
+  };
+  navTrigger.addEventListener('click', () => {
+    const opening = !navSheet.classList.contains('open');
+    navSheet.classList.toggle('open', opening);
+    navScrim.classList.toggle('open', opening);
+    navTrigger.setAttribute('aria-expanded', String(opening));
+  });
+  navScrim.addEventListener('click', closeMobileNav);
+  // Any of the three zones (Accueil, a library, Listes de lecture) -
+  // the sheet itself has no other clickable children, so this one
+  // delegated listener covers all of them without a per-link handler.
+  navSheet.addEventListener('click', (e) => {
+    if ((e.target as HTMLElement).closest('.navItem')) closeMobileNav();
+  });
+  window.addEventListener('hashchange', closeMobileNav);
+
+  // Drag-to-dismiss on the grabber handle only - not the whole sheet,
+  // which would fight the library grid's own scroll/tap targets (see
+  // docs/architecture.md's "Mobile navigation, take two"). Reported
+  // directly: without this, a scrim tap was the ONLY way to close the
+  // sheet, and the instinctive swipe-it-down gesture instead fell
+  // through to the browser's own pull-to-refresh (see Shell.css's
+  // touch-action/overscroll-behavior on the scrim/sheet themselves -
+  // this is the other half, giving that swipe something to actually do).
+  const CLOSE_DRAG_THRESHOLD_PX = 90;
+  const grabberHandle = appEl.querySelector('#sheetGrabberHandle') as HTMLElement;
+  let dragStartY: number | null = null;
+  let dragDeltaY = 0;
+
+  grabberHandle.addEventListener('pointerdown', (e) => {
+    dragStartY = e.clientY;
+    dragDeltaY = 0;
+    grabberHandle.setPointerCapture(e.pointerId);
+    navSheet.classList.add('dragging');
+  });
+  grabberHandle.addEventListener('pointermove', (e) => {
+    if (dragStartY === null) return;
+    dragDeltaY = Math.max(0, e.clientY - dragStartY); // only follows a downward drag - closing is the only thing this gesture does
+    navSheet.style.transform = `translateY(${dragDeltaY}px)`;
+  });
+  function endDrag() {
+    if (dragStartY === null) return;
+    dragStartY = null;
+    navSheet.classList.remove('dragging');
+    navSheet.style.transform = ''; // hands back to the .open class's own rule - either translateY(0) (snap back) or the closeMobileNav() call below immediately overrides it anyway
+    if (dragDeltaY > CLOSE_DRAG_THRESHOLD_PX) closeMobileNav();
+  }
+  grabberHandle.addEventListener('pointerup', endDrag);
+  grabberHandle.addEventListener('pointercancel', endDrag);
+
   return appEl.querySelector('#mainContent') as HTMLElement;
 }

client/src/styles/base.css

@@ -14,6 +14,7 @@
   --accent: #52b54b;          /* Emby's theme-primary-color (hsl(116, 41.7%, 50.2%)) */
   --accent-bright: #6ccf65;   /* Emby's --theme-accent-text-color-darkbg */
   --danger: #ff6b6b;
+  --mobile-topbar-h: 49px;    /* shell/Shell.css's .mobileTopBar - a fixed height so any other sticky element (e.g. views/library's .libraryHeader) can stack directly below it instead of guessing its rendered height */
 }
 
 * { box-sizing: border-box; }

client/src/styles/trackList.css

@@ -20,9 +20,25 @@
 .trackIndex { color: var(--muted); font-size: 13px; text-align: center; }
 .trackName { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
 .trackDuration { color: var(--muted); font-size: 12px; font-variant-numeric: tabular-nums; }
-.trackRow button { flex-shrink: 0; padding: 6px 10px; font-size: 12px; }
 
-@media (max-width: 600px) {
-  .trackRow { grid-template-columns: 24px 1fr; }
-  .trackRow .trackDuration, .trackRow button { grid-column: 2; justify-self: start; }
+/* A compact circle, not the wide text button this used to be (views/album's
+   own "Écouter ensemble"/"Ajouter à la file") - with a whole album's worth
+   of these stacked in a list, one word-length pill per row read as
+   noisier than the same action shown as a plain play/plus icon, the
+   same density real track lists use. */
+.trackRow button.trackIconBtn {
+  flex-shrink: 0;
+  width: 28px;
+  height: 28px;
+  padding: 0;
+  border-radius: 50%;
+  background: none;
+  border: 1px solid rgba(255, 255, 255, .18);
+  color: var(--muted);
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
+
+.trackRow button.trackIconBtn:hover { border-color: var(--text); color: var(--text); background: none; }
+.trackRow button.trackIconBtn svg { width: 12px; height: 12px; }

client/src/tiles.css

@@ -4,17 +4,34 @@
 /* base.css's global `input {}` rule already gives this the right look
    (padding/border/background) - this just bounds its width and spaces it
    from the grid below, shared by views/library, views/artist, views/album -
-   see tiles.ts's wireSearchFilter. */
+   see tiles.ts's wireSearchFilter. Sticky, not just top-of-page: asked
+   for directly, so it stays reachable while scrolling a long grid
+   instead of scrolling away with the page title above it. Its own
+   background (base.css's input rule already gives it var(--panel), not
+   transparent) is what keeps tiles scrolling underneath from showing
+   through its own bounds once stuck. */
 .searchBar {
   max-width: 320px;
   margin-bottom: 16px;
+  position: sticky;
+  top: 0;
+  z-index: 2;
 }
 
 .searchEmpty { margin-top: 8px; }
 
+/* The 160px floor was too wide for a real phone once .mainContent's own
+   side padding is subtracted - reported directly: a ~360-393px-wide
+   viewport (a common real Android width, not a rare edge case) only
+   ever fit one column. clamp(), not a max-width media query breakpoint:
+   this scales the minimum continuously with the viewport instead of
+   jumping at one arbitrary width, so it's already right at every size
+   in between, not just "mobile" and "desktop" - 28vw lands close to
+   100px on a narrow phone and hits the 160px ceiling (today's exact
+   desktop value, unchanged) well before any actual desktop width. */
 .grid {
   display: grid;
-  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
+  grid-template-columns: repeat(auto-fill, minmax(clamp(100px, 28vw, 160px), 1fr));
   gap: 20px 16px;
 }
 
@@ -127,3 +144,33 @@
   }
   .tileBtn { font-size: 11px; padding: 6px 4px; }
 }
+
+/* Artist/album tiles (tiles.ts's artistTileHtml/albumTileHtml) - an <a>
+   directly, not a <div> with a separate absolutely-positioned
+   .tileLink/.tileOverlay on top of it: there's only ever the one
+   action (open the artist/album page), so the whole tile just being
+   the link is simpler than reusing machinery built for a second,
+   hover-revealed set of actions these two never have. */
+.tile.tileArtist,
+.tile.tileAlbum {
+  text-decoration: none;
+  color: var(--text);
+}
+
+.tile.tileArtist img,
+.tile.tileAlbum img {
+  aspect-ratio: 1 / 1;
+}
+
+.tile.tileArtist img {
+  border-radius: 50%;
+}
+
+.tile.tileArtist .tileLabel {
+  text-align: center;
+}
+
+.tile.tileArtist:hover .tileLabel,
+.tile.tileAlbum:hover .tileLabel {
+  text-decoration: underline;
+}

client/src/tiles.ts

@@ -2,6 +2,7 @@
 // grid, and the artist page, so they all stay visually/behaviorally
 // identical instead of drifting.
 import './tiles.css';
+import { showToast } from './toast';
 import type { ItemDto } from './types';
 
 export function escapeHtml(str: string): string {
@@ -49,10 +50,20 @@ const DRILL_DOWN: Record<string, { route: string; label: string }> = {
   Playlist: { route: 'playlist', label: 'Voir la playlist' }
 };
 
-export function tileHtml(item: ItemDto): string {
+/**
+ * A poster tile - movies/shows/musicvideos/playlists, anything that
+ * still gets Emby's own portrait artwork. MusicArtist/MusicAlbum get a
+ * completely different shape below (a circle/a square, no hover
+ * overlay) since a movie poster's proportions and "hover for actions"
+ * pattern never fit an artist photo or an album cover - see
+ * docs/architecture.md's "Music UI rework".
+ */
+function posterTileHtml(item: ItemDto): string {
   const drill = item.type ? DRILL_DOWN[item.type] : undefined;
   const drillHref = drill ? `#/${drill.route}/${item.id}` : null;
-  const partyLabel = item.type === 'Audio' ? 'Écouter ensemble' : 'Lancer une watch party';
+  // Video -> "watch party", audio -> "listen party" - see the party kinds
+  // in docs/architecture.md (the third, "lounge party", is the static one).
+  const partyLabel = item.type === 'Audio' ? 'Lancer une listen party' : 'Lancer une watch party';
   return `
     <div class="tile">
       ${drillHref ? `<a href="${drillHref}" class="tileLink" aria-label="${escapeHtml(item.name)}"></a>` : ''}
@@ -67,7 +78,47 @@ export function tileHtml(item: ItemDto): string {
 }
 
 /**
- * Wires up every "Lancer une watch party" button inside `container`, now
+ * An artist tile - a circle, the one shape every music app uses for a
+ * person/act, never a rectangle. No hover overlay at all: unlike a
+ * poster tile, there's only ever one thing to do with an artist photo
+ * (open the artist page), so the whole tile is just that one link -
+ * see DRILL_DOWN's own MusicArtist entry.
+ */
+function artistTileHtml(item: ItemDto): string {
+  return `
+    <a href="#/artist/${item.id}" class="tile tileArtist" aria-label="${escapeHtml(item.name)}">
+      <img src="${item.imageUrl}" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
+      <span class="tileLabel">${escapeHtml(item.name)}</span>
+    </a>`;
+}
+
+/** An album tile - square, matching the cover art's own real proportions
+ *  (a movie-poster 2:3 box only ever stretched/cropped it oddly). Same
+ *  "whole tile is the one link" reasoning as artistTileHtml above. */
+function albumTileHtml(item: ItemDto): string {
+  return `
+    <a href="#/album/${item.id}" class="tile tileAlbum" aria-label="${escapeHtml(item.name)}">
+      <img src="${item.imageUrl}" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
+      <span class="tileLabel">${escapeHtml(item.name)}${item.year ? ` (${item.year})` : ''}</span>
+    </a>`;
+}
+
+/**
+ * Renders one item as a tile - the shape depends entirely on its Emby
+ * type. Dispatching here, rather than making every call site
+ * (home carousels, views/library, views/artist) pick a renderer itself,
+ * is what keeps them all visually/behaviorally identical instead of
+ * drifting - same reasoning this module's own header comment already
+ * gives for being shared in the first place.
+ */
+export function tileHtml(item: ItemDto): string {
+  if (item.type === 'MusicArtist') return artistTileHtml(item);
+  if (item.type === 'MusicAlbum') return albumTileHtml(item);
+  return posterTileHtml(item);
+}
+
+/**
+ * Wires up every "Lancer une watch/listen party" button inside `container`, now
  * and for any tile added to it later. `onStart(itemId)` does the actual
  * work (create the party + navigate) - kept as a caller-supplied callback
  * so this module doesn't need to depend on api/party.ts/router.ts itself.
@@ -83,14 +134,15 @@ export function wireTileButtons(container: ParentNode, onStart: (itemId: string)
     const btn = (e.target as HTMLElement).closest<HTMLButtonElement>('.startPartyBtn');
     if (!btn || btn.disabled) return;
     e.preventDefault();
+    const idleLabel = btn.textContent; // "watch party" or "listen party" - put back as-is on failure
     btn.disabled = true;
     btn.textContent = 'Démarrage...';
     try {
       await onStart(btn.dataset.itemId as string);
     } catch (err) {
-      alert((err as Error).message);
+      showToast((err as Error).message, { variant: 'error' });
       btn.disabled = false;
-      btn.textContent = 'Lancer une watch party';
+      btn.textContent = idleLabel;
     }
   });
 }

client/src/toast.css

@@ -0,0 +1,46 @@
+/* ---- Global toast notifications - see toast.ts. Same light-pill,
+   auto-dismiss visual language as views/player/Player.css's own
+   .requestBanner, generalized to work from any page (position: fixed
+   against the viewport, not the player specifically) since this is
+   used well beyond it now (host handoff, every "couldn't start/join a
+   party" error that used to be a blocking alert()). ---- */
+.toastContainer {
+  position: fixed;
+  top: max(16px, env(safe-area-inset-top, 0px));
+  left: 50%;
+  transform: translateX(-50%);
+  z-index: 100;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 8px;
+  max-width: calc(100% - 32px);
+  pointer-events: none;
+}
+
+.toast {
+  max-width: 100%;
+  background: var(--bg-header);
+  color: var(--text);
+  padding: 10px 18px;
+  border-radius: 20px;
+  font-size: 13px;
+  text-align: center;
+  box-shadow: 0 4px 16px rgba(0, 0, 0, .35);
+  opacity: 0;
+  transform: translateY(-8px);
+  transition: opacity .2s ease, transform .2s ease;
+}
+
+.toast.toastIn { opacity: 1; transform: translateY(0); }
+.toast.toastOut { opacity: 0; }
+
+/* Only variant beyond the default light/neutral pill above - a plain
+   left accent, not a loud red fill: still meant to be noticed without
+   the app suddenly shouting at you (see toast.ts's own comment on why
+   this stays this restrained even for errors). */
+.toast--error { border-left: 3px solid var(--danger); }
+
+@media (prefers-reduced-motion: reduce) {
+  .toast { transition: none; transform: none; }
+}

client/src/toast.ts

@@ -0,0 +1,66 @@
+import './toast.css';
+
+/**
+ * Global, light-touch notifications - replaces the blocking `alert()`
+ * this app used to reach for everywhere, from "you're now the host"
+ * (a status update, not something to interrupt anyone for) down to
+ * "couldn't start that party" (still just a message, not worth
+ * freezing the whole page over). Self-mounting (appends its own
+ * container to `document.body` on first use) rather than something
+ * Shell.ts wires up like musicBar/MusicBar - there's no per-party
+ * state to attach here, just a place to drop text that outlives
+ * whichever view happened to trigger it, so a plain module-level
+ * singleton is all this needs.
+ */
+
+let container: HTMLElement | null = null;
+
+function getContainer(): HTMLElement {
+  if (!container) {
+    container = document.createElement('div');
+    container.className = 'toastContainer';
+    document.body.appendChild(container);
+  }
+  return container;
+}
+
+export type ToastVariant = 'info' | 'error';
+
+export interface ToastOptions {
+  /** 'error' adds a left accent - still the same restrained pill, not
+   *  a red banner, since even a failed "start a party" click doesn't
+   *  warrant this app suddenly shouting. Default 'info'. */
+  variant?: ToastVariant;
+  /** Milliseconds before it fades back out on its own - there's no
+   *  manual dismiss button, same as Player.ts's own .requestBanner. */
+  duration?: number;
+}
+
+const DEFAULT_DURATION_MS = 4500;
+
+export function showToast(message: string, options: ToastOptions = {}): void {
+  const { variant = 'info', duration = DEFAULT_DURATION_MS } = options;
+
+  const el = document.createElement('div');
+  el.className = `toast${variant === 'error' ? ' toast--error' : ''}`;
+  el.textContent = message;
+  getContainer().appendChild(el);
+
+  // Two rAFs, not one: the element needs a full layout/style pass in
+  // its *starting* state (opacity 0) before the class add is what
+  // triggers the transition - adding it in the very same frame the
+  // node was inserted can get coalesced with the insert itself, and
+  // the "fade in" never visibly happens.
+  requestAnimationFrame(() => requestAnimationFrame(() => el.classList.add('toastIn')));
+
+  setTimeout(() => {
+    el.classList.remove('toastIn');
+    el.classList.add('toastOut');
+    el.addEventListener('transitionend', () => el.remove(), { once: true });
+    // Belt-and-suspenders for prefers-reduced-motion (transition: none
+    // there - see toast.css) - 'transitionend' never fires with no
+    // transition running, which would otherwise leave this in the DOM
+    // forever instead of just skipping straight to removed.
+    setTimeout(() => el.remove(), 300);
+  }, duration);
+}

client/src/types.ts

@@ -9,6 +9,10 @@
 export interface ItemDto {
   id: string;
   name: string;
+  /** Emby's own sort key (articles stripped) when the server requested
+   *  it, the display name otherwise - see server/src/types.ts's own
+   *  ItemDto.sortName for why alphaIndex.ts buckets by this, not name. */
+  sortName: string;
   overview?: string;
   year?: number;
   type?: string;
@@ -50,6 +54,16 @@ export interface PlaybackOptionsDto {
   subtitleTracks: PlaybackTrackOption[];
 }
 
+/** Emby's own native intro/credits detection - see server/src/types.ts's
+ *  own copy of this shape for where the field names come from. Every
+ *  field is independently nullable ("not detected", never an error) -
+ *  see views/player/Player.ts's updateSkipButton, the only consumer. */
+export interface PlaybackMarkersDto {
+  introStartTicks: number | null;
+  introEndTicks: number | null;
+  creditsStartTicks: number | null;
+}
+
 export type MediaType = 'video' | 'music';
 
 export interface PublicMember {
@@ -157,6 +171,42 @@ export interface LobbyPartyDto {
   positionTicks: number | null;
   isPaused: boolean | null;
   positionUpdatedUtc: number | null;
+  /** The static watch party this live session belongs to, if any. */
+  staticPartyId: string | null;
+  staticPartyName: string | null;
+}
+
+/** Mirrors server/src/types.ts's StaticPartySummaryDto - one static
+ *  (persistent) watch party, as the home page lists it. */
+export interface StaticPartySummaryDto {
+  id: string;
+  name: string;
+  sourceType: 'series' | 'season' | 'playlist';
+  imageUrl: string;
+  itemCount: number;
+  groupWatchedCount: number;
+  nextItemName: string | null;
+  memberCount: number;
+  youAreMember: boolean;
+  youAreCreator: boolean;
+  missedCount: number;
+  livePartyId: string | null;
+}
+
+/** One item of a static watch party - mirrors StaticPartyItemDto. */
+export interface StaticPartyItemDto {
+  itemId: string;
+  itemName: string;
+  itemImageUrl: string;
+  groupState: 'watched' | 'next' | 'upcoming';
+  viewerWatched: boolean;
+}
+
+/** Mirrors server/src/types.ts's StaticPartyDetailDto. */
+export interface StaticPartyDetailDto extends StaticPartySummaryDto {
+  items: StaticPartyItemDto[];
+  missedItemIds: string[];
+  members: Array<{ userId: string; userName: string; watchedCount: number; isCreator: boolean }>;
 }
 
 export interface ItemChangedMsg {

client/src/views/album/Album.css

@@ -1,3 +1,9 @@
+/* .albumHeader's own two children - .seriesInfo (Series.css) and
+   .playlistActions (Playlist.css) - are reused as-is, same precedent
+   Album.css already set for .seriesInfo itself: every route's CSS ends
+   up in the one bundle regardless of which view imports it, so there's
+   no need to duplicate a rule this generic (a flex row of actions under
+   a title) just because it was first written for a different page. */
 .albumHeader {
   display: flex;
   gap: 20px;

client/src/views/album/Album.html

@@ -2,10 +2,14 @@
 <div class="albumHeader">
   <img class="albumCover" id="albumCover" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
   <div class="seriesInfo">
+    <span class="heroKicker" id="albumKicker">Album</span>
     <h1 id="albumTitle"></h1>
     <p class="hint hide" id="albumArtist"></p>
+    <div class="heroActions">
+      <button id="launchBtn" class="heroPlayBtn"><span class="heroPlayIcon" id="launchBtnIcon"></span><span id="launchBtnLabel">Écouter cet album</span></button>
       <a class="linklike" id="embyLink" target="_blank" rel="noopener">Voir sur Emby</a>
     </div>
+  </div>
 </div>
 <input id="searchInput" class="searchBar" type="search" placeholder="Rechercher un morceau..." />
 <p class="hint searchEmpty hide">Aucun résultat.</p>

client/src/views/album/Album.ts

@@ -2,15 +2,23 @@ import './Album.css';
 import '../../styles/trackList.css';
 import html from './Album.html';
 import { getAlbumTracks, getItem } from '../../api/embyApi';
-import { addTrackToQueue, createParty } from '../../api/party';
+import { addTrackToQueue, createParty, queueItem } from '../../api/party';
 import { getActiveMusicPartyId, joinMusicParty } from '../../musicBar/MusicBar';
 import { escapeHtml, formatDuration, wireSearchFilter } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
+import { showToast } from '../../toast';
 import type { ItemDto, MusicTrackInput } from '../../types';
 import type { RouteParams } from '../../router';
 
 const TICKS_PER_SECOND = 10000000; // Emby/.NET convention: 1 tick = 100ns, same as everywhere else this app touches durations/positions
 
+// Same "small local constant" convention as musicBar/MusicBar.ts's own
+// icon strings - PLAY_ICON_SVG is duplicated from views/artist/Artist.ts
+// rather than shared, see that file's own comment on why.
+const PLAY_ICON_SVG = '<svg viewBox="0 0 24 24" aria-hidden="true"><path d="M6 4.5v15l14-7.5Z" fill="currentColor"></path></svg>';
+const PLUS_ICON_SVG = '<svg viewBox="0 0 24 24" aria-hidden="true"><line x1="12" y1="5" x2="12" y2="19" stroke="currentColor" stroke-width="2.2" stroke-linecap="round"></line><line x1="5" y1="12" x2="19" y2="12" stroke="currentColor" stroke-width="2.2" stroke-linecap="round"></line></svg>';
+const CHECK_ICON_SVG = '<svg viewBox="0 0 24 24" aria-hidden="true"><path d="M4 12.5 9 17.5 20 6.5" fill="none" stroke="currentColor" stroke-width="2.2" stroke-linecap="round" stroke-linejoin="round"></path></svg>';
+
 /** Route `/album/:id` - the last level of the music hierarchy: one album's
  *  tracks, each startable as its own listen party (mirrors views/series's
  *  episode list, but flat - an album has no further sub-level the way a
@@ -31,9 +39,9 @@ export async function renderAlbum(root: HTMLElement, params: RouteParams): Promi
   root.innerHTML = html;
   root.querySelector('#back')!.addEventListener('click', () => history.back());
   (root.querySelector('#albumCover') as HTMLImageElement).src = album.imageUrl;
-  root.querySelector('#albumTitle')!.innerHTML = album.year
-    ? `${escapeHtml(album.name)} <span class="seriesYear">(${album.year})</span>`
-    : escapeHtml(album.name);
+  root.querySelector('#albumKicker')!.textContent = album.year ? `Album · ${album.year}` : 'Album';
+  root.querySelector('#albumTitle')!.textContent = album.name;
+  root.querySelector('#launchBtnIcon')!.innerHTML = PLAY_ICON_SVG;
   if (album.artistName) {
     const artistEl = root.querySelector('#albumArtist')!;
     artistEl.textContent = album.artistName;
@@ -42,27 +50,36 @@ export async function renderAlbum(root: HTMLElement, params: RouteParams): Promi
   (root.querySelector('#embyLink') as HTMLAnchorElement).href = album.embyUrl;
 
   const listEl = root.querySelector('#trackList')!;
+  const launchBtn = root.querySelector('#launchBtn') as HTMLButtonElement;
+  const launchBtnLabel = root.querySelector('#launchBtnLabel')!;
   if (!tracks.length) {
     listEl.innerHTML = '<p class="hint">Aucun morceau dans cet album.</p>';
     root.querySelector('#searchInput')!.remove();
+    launchBtn.disabled = true;
     return;
   }
 
-  // Label reflects whether a listen party is already active *at render
-  // time* - a harmless, occasionally-stale label (see refreshLabels()
-  // below for when it's corrected). The actual behavior on click always
-  // re-checks getActiveMusicPartyId() fresh, so clicking never does the
-  // wrong thing even if the label itself hasn't caught up yet (e.g.
-  // someone hit "Quitter" on the bar while this page was already open).
-  const startLabel = 'Écouter ensemble';
+  // aria-label reflects whether a listen party is already active *at
+  // render time* - a harmless, occasionally-stale label (see
+  // refreshLabels() below for when it's corrected). The actual behavior
+  // on click always re-checks getActiveMusicPartyId() fresh, so clicking
+  // never does the wrong thing even if the label hasn't caught up yet
+  // (e.g. someone hit "Quitter" on the bar while this page was already
+  // open). Icon-only buttons (play vs plus, mirroring the same two
+  // states) - the label lives in aria-label/title for accessibility
+  // rather than as visible text, now that there's one per track instead
+  // of one per page (see docs/architecture.md's "Music UI rework").
+  const startLabel = 'Lancer une listen party';
   const addLabel = 'Ajouter à la file';
+  const startAlbumLabel = 'Écouter cet album';
+  const addAlbumLabel = "Ajouter l'album à la file";
 
   listEl.innerHTML = tracks.map((t) => `
     <div class="trackRow">
       <span class="trackIndex">${t.indexNumber != null ? t.indexNumber : ''}</span>
       <span class="trackName">${escapeHtml(t.name)}</span>
       <span class="trackDuration">${t.durationTicks ? formatDuration(t.durationTicks / TICKS_PER_SECOND) : ''}</span>
-      <button class="startPartyBtn" data-item-id="${t.id}">${getActiveMusicPartyId() ? addLabel : startLabel}</button>
+      <button class="startPartyBtn trackIconBtn" data-item-id="${t.id}" title="${getActiveMusicPartyId() ? addLabel : startLabel}" aria-label="${getActiveMusicPartyId() ? addLabel : startLabel}">${getActiveMusicPartyId() ? PLUS_ICON_SVG : PLAY_ICON_SVG}</button>
     </div>
   `).join('');
 
@@ -77,14 +94,22 @@ export async function renderAlbum(root: HTMLElement, params: RouteParams): Promi
     };
   }
 
-  // Re-labels every track button from current state, not just the one
-  // just clicked - starting a party from track 3 means tracks 1, 2 and 4
-  // can now also be queued instead of starting a party of their own.
+  // Re-labels every track button (and the whole-album one) from current
+  // state, not just the one just clicked - starting a party from track 3
+  // means tracks 1, 2 and 4 can now also be queued instead of starting a
+  // party of their own.
   function refreshLabels(): void {
+    const active = getActiveMusicPartyId();
     listEl.querySelectorAll<HTMLButtonElement>('.startPartyBtn').forEach((b) => {
-      if (!b.disabled) b.textContent = getActiveMusicPartyId() ? addLabel : startLabel;
+      if (b.disabled) return;
+      const label = active ? addLabel : startLabel;
+      b.innerHTML = active ? PLUS_ICON_SVG : PLAY_ICON_SVG;
+      b.title = label;
+      b.setAttribute('aria-label', label);
     });
+    if (!launchBtn.disabled) launchBtnLabel.textContent = active ? addAlbumLabel : startAlbumLabel;
   }
+  refreshLabels(); // sets launchBtn's own initial label - the per-track buttons already get theirs from the template above
 
   listEl.querySelectorAll<HTMLButtonElement>('.startPartyBtn').forEach((btn, i) => {
     const track = tracks[i] as ItemDto;
@@ -93,10 +118,8 @@ export async function renderAlbum(root: HTMLElement, params: RouteParams): Promi
       const activePartyId = getActiveMusicPartyId();
       try {
         if (activePartyId) {
-          btn.textContent = 'Ajout...';
           await addTrackToQueue(activePartyId, trackInputFor(track));
         } else {
-          btn.textContent = 'Démarrage...';
           // Attaches the persistent bottom bar directly and stays right
           // here - no navigate() - so adding a few more tracks from this
           // same album is just clicking their buttons too. See
@@ -105,15 +128,42 @@ export async function renderAlbum(root: HTMLElement, params: RouteParams): Promi
           const party = await createParty(track.id);
           joinMusicParty(party.partyId, party);
         }
-        btn.textContent = 'Ajouté !';
+        btn.innerHTML = CHECK_ICON_SVG;
         setTimeout(() => { btn.disabled = false; refreshLabels(); }, 1500);
       } catch (err) {
-        alert((err as Error).message);
+        showToast((err as Error).message, { variant: 'error' });
         btn.disabled = false;
         refreshLabels();
       }
     });
   });
 
+  // Whole-album equivalent of the per-track buttons above - asked for
+  // directly, alongside the same action for a whole artist (see
+  // Artist.ts). itemId is the album itself, not any one track - the
+  // server expands it into every track inside, in order (see index.ts's
+  // resolveMusicTracksForItem/createMusicPartyFromTracks), the same way
+  // launching a playlist already expands into everything it contains.
+  launchBtn.addEventListener('click', async () => {
+    launchBtn.disabled = true;
+    const activePartyId = getActiveMusicPartyId();
+    try {
+      if (activePartyId) {
+        launchBtnLabel.textContent = 'Ajout...';
+        await queueItem(activePartyId, albumId);
+      } else {
+        launchBtnLabel.textContent = 'Démarrage...';
+        const party = await createParty(albumId);
+        joinMusicParty(party.partyId, party);
+      }
+      launchBtnLabel.textContent = 'Ajouté !';
+      setTimeout(() => { launchBtn.disabled = false; refreshLabels(); }, 1500);
+    } catch (err) {
+      showToast((err as Error).message, { variant: 'error' });
+      launchBtn.disabled = false;
+      refreshLabels();
+    }
+  });
+
   wireSearchFilter(root.querySelector('#searchInput') as HTMLInputElement, root, '.trackRow');
 }

client/src/views/artist/Artist.css

@@ -0,0 +1,89 @@
+/* ---- Artist hero - see Artist.ts. A circular photo, never a poster:
+   the same reasoning tiles.ts's artistTileHtml already gives for the
+   artist grid applies just as much to the one photo at the top of the
+   artist's own page. ---- */
+.artistHero {
+  display: flex;
+  align-items: flex-end;
+  gap: 20px;
+  margin-bottom: 24px;
+}
+
+.artistHeroPhoto {
+  width: 132px;
+  height: 132px;
+  border-radius: 50%;
+  object-fit: cover;
+  background: var(--panel);
+  flex-shrink: 0;
+}
+
+.artistHeroPhoto.noImage { visibility: hidden; }
+
+.artistHeroInfo {
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+  min-width: 0;
+}
+
+.artistHeroInfo h1 { margin: 0; font-size: 26px; line-height: 1.15; }
+
+/* ---- Shared with views/album's own hero (Album.css reuses these three
+   classes directly rather than redefining them - same "one rule,
+   whichever file needs it first" precedent Album.css already set for
+   .seriesInfo/.playlistActions). ---- */
+.heroKicker {
+  font-size: 12px;
+  color: var(--muted);
+  text-transform: uppercase;
+  letter-spacing: .05em;
+  font-weight: 600;
+}
+
+.heroActions {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+  margin-top: 10px;
+  flex-wrap: wrap;
+}
+
+/* A pill, not a plain rectangular button - the one visual actually
+   borrowed from real music apps' big circular play button, while
+   keeping the explicit text label this app already standardized on
+   for every request/action control (see docs/architecture.md's
+   player-rework section) - nothing here is icon-only. */
+.heroPlayBtn {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 6px 18px 6px 6px;
+  border-radius: 99px;
+  background: var(--panel);
+  color: var(--text);
+  font-size: 14px;
+  font-weight: 600;
+}
+
+.heroPlayBtn:hover { background: #333; }
+
+.heroPlayIcon {
+  width: 34px;
+  height: 34px;
+  border-radius: 50%;
+  background: var(--accent);
+  color: #fff;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  flex-shrink: 0;
+}
+
+.heroPlayIcon svg { width: 14px; height: 14px; display: block; }
+
+@media (max-width: 600px) {
+  .artistHero { flex-direction: column; align-items: center; text-align: center; }
+  .artistHeroPhoto { width: 104px; height: 104px; }
+  .artistHeroInfo { align-items: center; }
+}

client/src/views/artist/Artist.html

@@ -1,5 +1,15 @@
 <button class="linklike" id="back">&larr; Retour</button>
-<div class="pageHeader"><h1></h1></div>
+<div class="artistHero">
+  <img class="artistHeroPhoto" id="artistPhoto" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
+  <div class="artistHeroInfo">
+    <span class="heroKicker">Artiste</span>
+    <h1></h1>
+    <span class="hint" id="albumCount"></span>
+    <div class="heroActions">
+      <button id="launchBtn" class="heroPlayBtn"><span class="heroPlayIcon" id="launchBtnIcon"></span><span id="launchBtnLabel">Écouter toute la discographie</span></button>
+    </div>
+  </div>
+</div>
 <input id="searchInput" class="searchBar" type="search" placeholder="Rechercher un album..." />
 <p class="hint searchEmpty hide">Aucun résultat.</p>
 <div id="grid" class="grid"></div>

client/src/views/artist/Artist.ts

@@ -1,16 +1,28 @@
+import './Artist.css';
 import html from './Artist.html';
 import { getArtistAlbums, getItem } from '../../api/embyApi';
+import { createParty, queueItem } from '../../api/party';
+import { getActiveMusicPartyId, joinMusicParty } from '../../musicBar/MusicBar';
 import type { RouteParams } from '../../router';
 import { tileHtml, wireSearchFilter } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
+import { showToast } from '../../toast';
+
+// Same icon, same "small local constant" convention as musicBar/MusicBar.ts's
+// own PLAY_ICON_SVG - not shared from there since neither file otherwise
+// depends on the other, and duplicating one SVG string is cheaper than a
+// shared icons module for exactly two current call sites (here and
+// views/album/Album.ts).
+const PLAY_ICON_SVG = '<svg viewBox="0 0 24 24" aria-hidden="true"><path d="M6 4.5v15l14-7.5Z" fill="currentColor"></path></svg>';
 
 /** Route `/artist/:id` - one artist's albums, reached from a music
  *  library's top-level grid (see views/library) via a MusicArtist tile's
  *  "Voir les albums" link (tiles.ts's DRILL_DOWN table). Structurally the
  *  same "detail header + grid" shape as views/series, just one level up
- *  the music hierarchy (Artist -> Album, not Series -> Season/Episode) and
- *  with no per-item action beyond drilling further into an album (an
- *  artist has nothing itself to start a party from). */
+ *  the music hierarchy (Artist -> Album, not Series -> Season/Episode).
+ *  #launchBtn is the one action available at this level itself (every
+ *  album's own tracks, in one go) - drilling into a specific album is
+ *  still the only way to queue less than the whole discography. */
 export async function renderArtist(root: HTMLElement, params: RouteParams): Promise<void> {
   const artistId = params.id as string;
   root.innerHTML = LOADING_HINT;
@@ -26,14 +38,58 @@ export async function renderArtist(root: HTMLElement, params: RouteParams): Prom
 
   root.innerHTML = html;
   root.querySelector('h1')!.textContent = artist.name;
+  (root.querySelector('#artistPhoto') as HTMLImageElement).src = artist.imageUrl;
+  root.querySelector('#launchBtnIcon')!.innerHTML = PLAY_ICON_SVG;
   root.querySelector('#back')!.addEventListener('click', () => history.back());
 
+  const launchBtn = root.querySelector('#launchBtn') as HTMLButtonElement;
+  const launchBtnLabel = root.querySelector('#launchBtnLabel')!;
   const grid = root.querySelector('#grid')!;
+  root.querySelector('#albumCount')!.textContent = `${albums.length} album${albums.length > 1 ? 's' : ''}`;
   if (!albums.length) {
     grid.innerHTML = '<p class="hint">Aucun album trouvé pour cet artiste.</p>';
     root.querySelector('#searchInput')!.remove();
+    launchBtn.disabled = true;
     return;
   }
   grid.innerHTML = albums.map(tileHtml).join('');
   wireSearchFilter(root.querySelector('#searchInput') as HTMLInputElement, root, '.tile');
+
+  // Label reflects whether a listen party is already active - same
+  // "harmless, occasionally-stale until the next refresh" reasoning as
+  // views/album's own equivalent buttons (the click handler below
+  // always re-checks getActiveMusicPartyId() fresh regardless).
+  const startLabel = 'Écouter toute la discographie';
+  const addLabel = 'Ajouter la discographie à la file';
+  function refreshLabel(): void {
+    if (!launchBtn.disabled) launchBtnLabel.textContent = getActiveMusicPartyId() ? addLabel : startLabel;
+  }
+  refreshLabel();
+
+  // itemId is the artist itself - the server expands it into every
+  // album's tracks, in order, the same mechanism a whole-album launch
+  // uses one level down (see views/album/Album.ts, and index.ts's
+  // resolveMusicTracksForItem/createMusicPartyFromTracks).
+  launchBtn.addEventListener('click', async () => {
+    launchBtn.disabled = true;
+    const activePartyId = getActiveMusicPartyId();
+    try {
+      if (activePartyId) {
+        launchBtnLabel.textContent = 'Ajout...';
+        await queueItem(activePartyId, artistId);
+      } else {
+        launchBtnLabel.textContent = 'Démarrage...';
+        // Same "attach the bar, stay put" pattern as views/album - see
+        // its own comment.
+        const party = await createParty(artistId);
+        joinMusicParty(party.partyId, party);
+      }
+      launchBtnLabel.textContent = 'Ajouté !';
+      setTimeout(() => { launchBtn.disabled = false; refreshLabel(); }, 1500);
+    } catch (err) {
+      showToast((err as Error).message, { variant: 'error' });
+      launchBtn.disabled = false;
+      refreshLabel();
+    }
+  });
 }

client/src/views/home/Home.css

@@ -60,3 +60,18 @@
   color: var(--accent-bright);
   font-weight: 600;
 }
+
+/* Which kind of party a card is - "Watch party" (video) or "Listen party"
+   (audio). Lounge parties (static) have their own tab, never this list. */
+.partyKind {
+  align-self: flex-start;
+  font-size: 10px;
+  font-weight: 700;
+  letter-spacing: .06em;
+  text-transform: uppercase;
+  padding: 1px 6px;
+  border-radius: 4px;
+}
+
+.partyKind--video { color: var(--accent-bright); background: rgba(82, 181, 75, .15); }
+.partyKind--music { color: #7fb4ff; background: rgba(127, 180, 255, .15); }

client/src/views/home/Home.html

@@ -3,7 +3,7 @@
 </div>
 
 <section class="section" id="partiesSection" hidden>
-  <h2>Watch parties en cours</h2>
+  <h2>Parties en cours</h2>
   <div id="partiesCarousel" class="carousel"></div>
 </section>
 

client/src/views/home/Home.ts

@@ -6,6 +6,7 @@ import { getActiveMusicPartyId } from '../../musicBar/MusicBar';
 import { navigate } from '../../router';
 import { escapeHtml, tileHtml, wireTileButtons } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
+import { showToast } from '../../toast';
 import type { LobbyPartyDto } from '../../types';
 
 export function renderHome(root: HTMLElement): () => void {
@@ -17,7 +18,9 @@ export function renderHome(root: HTMLElement): () => void {
   // label is the one piece that ticks purely client-side (from
   // createdUtc) - no point re-pushing from the server once a second just
   // for a clock.
-  const lobby = connectLobby((parties) => renderParties(root, parties));
+  // A static watch party's sessions live in their own tab
+  // (views/staticParties), not here - this list is classic parties only.
+  const lobby = connectLobby((parties) => renderParties(root, parties.filter((p) => !p.staticPartyId)));
   const elapsedTimer = window.setInterval(() => updateElapsedLabels(root), 1000);
 
   loadRecentSections(root);
@@ -56,6 +59,7 @@ function renderParties(root: HTMLElement, parties: LobbyPartyDto[]): void {
     <div class="partyCard">
       <img class="${p.mediaType === 'music' ? 'partyCardArt--square' : ''}" src="${p.itemImageUrl || ''}" alt="" onerror="this.classList.add('noImage')" />
       <div class="partyCardInfo">
+        <span class="partyKind partyKind--${p.mediaType}">${p.mediaType === 'music' ? 'Listen party' : 'Watch party'}</span>
         <strong>${escapeHtml(p.itemName || '')}</strong>
         <span class="hint">
           ${escapeHtml(p.hostUserName || '')} · ${p.memberCount} participant${p.memberCount > 1 ? 's' : ''}
@@ -83,7 +87,7 @@ function renderParties(root: HTMLElement, parties: LobbyPartyDto[]): void {
         await joinParty(btn.dataset.partyId as string);
         navigate(`/party/${btn.dataset.partyId}`);
       } catch (err) {
-        alert((err as Error).message);
+        showToast((err as Error).message, { variant: 'error' });
         btn.disabled = false;
       }
     });

client/src/views/library/Library.css

@@ -0,0 +1,35 @@
+/* ---- Library page header (title + search bar) - see Library.ts/html. ----
+   Wraps .pageHeader and tiles.css's .searchBar (already sticky on its own)
+   in one sticky block so the title stays put too, instead of scrolling
+   away while the search bar stays behind - reported directly. Needs its
+   own opaque background since .pageHeader's <h1> has none - without it,
+   grid tiles scrolling underneath would show through the title text once
+   stuck. */
+.libraryHeader {
+  position: sticky;
+  top: 0;
+  /* Above 2, not just tiles.css's own .searchBar precedent: a tile's
+     .tileOverlay action buttons are ALSO z-index: 2, and (unlike the
+     slim .searchBar this header replaced) this header is tall enough
+     that a scrolling tile's own overlay - always-visible on touch, see
+     tiles.css's (hover: none) block - reaches it well before it's fully
+     scrolled past. Equal z-index ties break on paint order, and a tile
+     (inside #grid, after this header in the DOM) wins that tie -
+     reported directly as buttons rendering over the header while
+     scrolling. z-index: 3 matches shell/Shell.css's own .mobileTopBar,
+     the other sticky header this one already has to stack correctly
+     under on mobile. */
+  z-index: 3;
+  background: var(--bg);
+  padding-top: 4px;
+}
+
+/* Below 720px, shell/Shell.css's own sticky .mobileTopBar already occupies
+   top:0 - stacking this header at top:0 too would have both fighting over
+   the same spot, with this one (later in paint order) covering the app's
+   brand bar. Stick it right below instead. */
+@media (max-width: 720px) {
+  .libraryHeader {
+    top: var(--mobile-topbar-h);
+  }
+}

client/src/views/library/Library.html

@@ -1,4 +1,6 @@
-<div class="pageHeader"><h1></h1></div>
-<input id="searchInput" class="searchBar" type="search" placeholder="Rechercher dans cette bibliothèque..." />
+<div class="libraryHeader">
+  <div class="pageHeader"><h1></h1></div>
+  <input id="searchInput" class="searchBar" type="search" placeholder="Rechercher dans cette bibliothèque..." />
+</div>
 <p class="hint searchEmpty hide">Aucun résultat.</p>
 <div id="grid" class="grid"><p class="hint"><span class="spinner"></span>Chargement...</p></div>

client/src/views/library/Library.ts

@@ -1,9 +1,11 @@
+import './Library.css';
 import html from './Library.html';
 import { getArtists, getLibraries, getLibraryItems } from '../../api/embyApi';
 import { createParty } from '../../api/party';
 import { navigate } from '../../router';
-import type { RouteParams } from '../../router';
-import { renderTilesInChunks, wireSearchFilter, wireTileButtons } from '../../tiles';
+import type { CleanupFn, RouteParams } from '../../router';
+import { renderGroupedTilesInChunks, wireAlphaRail, wireSectionSearchSync } from '../../alphaIndex';
+import { wireSearchFilter, wireTileButtons } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
 
 /**
@@ -17,17 +19,30 @@ import { LOADING_HINT } from '../../loading';
  *     endpoint, not a generic library listing - see
  *     GET /api/catalog/libraries/:id/artists) - Album -> Tracks is one
  *     level further in (views/artist, then views/album).
+ *
+ * Synchronous wrapper around an async IIFE, not `async function`
+ * directly - router.ts's cleanup contract needs a CleanupFn back
+ * *synchronously*, which an async function returning a Promise can't
+ * do (see router.ts's own comment, and views/player/Player.ts's
+ * renderPartyPlayer for the same shape). `cancelled` guards every
+ * resume-after-await point so a still-in-flight fetch from a library
+ * the user already navigated away from can't clobber whatever route
+ * rendered after it.
  */
-export async function renderLibrary(root: HTMLElement, params: RouteParams): Promise<void> {
+export function renderLibrary(root: HTMLElement, params: RouteParams): CleanupFn {
   root.innerHTML = LOADING_HINT;
+  let cancelled = false;
+  let cleanup: CleanupFn = () => {};
 
+  (async () => {
     let libraries;
     try {
       libraries = await getLibraries();
     } catch {
-    root.innerHTML = '<p class="error">Impossible de charger les bibliothèques.</p>';
+      if (!cancelled) root.innerHTML = '<p class="error">Impossible de charger les bibliothèques.</p>';
       return;
     }
+    if (cancelled) return;
 
     const library = libraries.find((l) => l.id === params.id);
     if (!library) {
@@ -45,20 +60,32 @@ export async function renderLibrary(root: HTMLElement, params: RouteParams): Pro
         ? await getArtists(library.id)
         : await getLibraryItems(library.id);
     } catch {
+      if (!cancelled) {
         grid.innerHTML = '<p class="error">Impossible de charger cette bibliothèque.</p>';
         root.querySelector('#searchInput')!.remove();
+      }
       return;
     }
+    if (cancelled) return;
     if (!items.length) {
       grid.innerHTML = '<p class="hint">Bibliothèque vide.</p>';
       root.querySelector('#searchInput')!.remove();
       return;
     }
 
-  renderTilesInChunks(grid, items);
+    renderGroupedTilesInChunks(grid, items);
     wireTileButtons(grid, async (itemId) => {
       const party = await createParty(itemId);
       navigate(`/party/${party.partyId}`);
     });
-  wireSearchFilter(root.querySelector('#searchInput') as HTMLInputElement, root, '.tile');
+    const searchInput = root.querySelector('#searchInput') as HTMLInputElement;
+    wireSearchFilter(searchInput, root, '.tile');
+    wireSectionSearchSync(searchInput, grid);
+    cleanup = wireAlphaRail(root, grid, items);
+  })();
+
+  return () => {
+    cancelled = true;
+    cleanup();
+  };
 }

client/src/views/player/Player.css

@@ -196,6 +196,26 @@
   transition: padding .25s ease, background-color .25s ease, border-color .25s ease;
 }
 
+/* Floating above #bottomBar (higher z-index, positioned clear of its
+   tallest/expanded height) rather than living inside it - see
+   Player.html's own comment on why: it must stay reachable through the
+   bar's own auto-hide/.minimal collapse, not disappear along with it. */
+.skipMarkerBtn {
+  position: absolute;
+  right: 10px;
+  bottom: 84px;
+  z-index: 7;
+  background: rgba(20, 18, 22, .85);
+  color: white;
+  border: 1px solid rgba(255, 255, 255, .25);
+  padding: 10px 18px;
+  border-radius: 6px;
+  font-size: 13px;
+  font-weight: 600;
+}
+
+.skipMarkerBtn:hover { background: rgba(20, 18, 22, .95); border-color: rgba(255, 255, 255, .4); }
+
 /* Collapsed down to just the seek bar after a stretch of no activity
    (see Player.ts's scheduleControlsHide) - asked for directly: the
    full bar, always visible, sits right where a native <track> subtitle
@@ -346,6 +366,15 @@
 
 .fsBtn:hover { background: rgba(255, 255, 255, .18); }
 
+/* #pipBtn while active - same "clearly-on" treatment as .iconBtn's own
+   [aria-pressed="true"] rule (#castBtn), just scoped to .fsBtn instead -
+   the two aren't combined onto one shared class since .iconBtn and
+   .fsBtn otherwise disagree on padding/border-radius/background. */
+.fsBtn[aria-pressed="true"] {
+  color: #ff9800;
+  background: rgba(255, 152, 0, .18);
+}
+
 /* Replaces the video content while casting - the local <video> is
    paused/torn down (see Player.ts's startCasting/cast.ts), so leaving
    its last frame frozen with no explanation would just look stuck. */

client/src/views/player/Player.html

@@ -63,6 +63,17 @@
        notification rather than a fourth thing bolted onto a fixed layout. -->
   <div id="requestBanner" class="requestBanner hide"></div>
 
+  <!-- Emby's own native intro detection (see Player.ts's updateSkipButton/
+       CatalogService.getPlaybackMarkers) - shown independently of #bottomBar
+       below, and NOT subject to its own auto-hide/.minimal collapse, since
+       this needs to stay reachable the moment the intro starts even if
+       nobody's touched the player yet. Host-only, like every other seek -
+       see updateSkipButton's own comment for why a follower can't get this
+       button at all. Explicit label, not just an icon - see
+       docs/architecture.md's player-rework section for why this app
+       standardized on that for every request-shaped control. -->
+  <button id="skipIntroBtn" class="skipMarkerBtn hide">Passer l'intro</button>
+
   <!-- One bar, bottom-anchored, replacing what used to be three separate
        floating pieces (a centered banner/notice column, a request
        toolbar cornered bottom-right, an "Épisode suivant" link up in the
@@ -116,6 +127,17 @@
         <span id="ambientNotice" class="ambientNotice hide"></span>
       </div>
       <div class="bottomBarZone right">
+        <!-- Hidden by default, shown only once Player.ts confirms
+             document.pictureInPictureEnabled - not every browser supports
+             this (see its own comment), and there's no live
+             "availability changed" event to react to the way the cast
+             button has, since this never changes mid-session. -->
+        <button id="pipBtn" class="fsBtn hide" title="Picture-in-picture" aria-label="Picture-in-picture" aria-pressed="false">
+          <svg viewBox="0 0 24 24" width="16" height="16" aria-hidden="true">
+            <rect x="3" y="4" width="18" height="14" rx="2" fill="none" stroke="currentColor" stroke-width="2"></rect>
+            <rect x="12" y="11" width="7" height="5" rx="1" fill="currentColor"></rect>
+          </svg>
+        </button>
         <button id="fullscreenBtn" class="fsBtn" title="Plein écran" aria-label="Plein écran"></button>
       </div>
     </div>

client/src/views/player/Player.ts

@@ -1,17 +1,19 @@
 import '../../styles/presence.css';
 import './Player.css';
 import html from './Player.html';
-import { auth, burnInStreamUrl, getPlaybackOptions, partyStreamUrl, subtitleUrl } from '../../api/embyApi';
+import { auth, burnInStreamUrl, getPlaybackMarkers, getPlaybackOptions, partyStreamUrl, subtitleUrl } from '../../api/embyApi';
 import { getParty, leaveParty, connectParty, issueCastToken, revokeCastToken } from '../../api/party';
 import type { PartyConnection } from '../../api/party';
 import { navigate } from '../../router';
 import type { CleanupFn, RouteParams } from '../../router';
 import { colorForName, escapeHtml, formatDuration, initialsFor } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
-import type { BurnInChangedMsg, ItemChangedMsg, PartyPublicState, PauseRequestedMsg, PlaybackOptionsDto, ResumeRequestedMsg, SocketMember, StreamOptionsChangedMsg, TextSubtitleChangedMsg } from '../../types';
+import { showToast } from '../../toast';
+import type { BurnInChangedMsg, ItemChangedMsg, PartyPublicState, PauseRequestedMsg, PlaybackMarkersDto, PlaybackOptionsDto, ResumeRequestedMsg, SocketMember, StreamOptionsChangedMsg, TextSubtitleChangedMsg } from '../../types';
 import { joinMusicParty, leaveMusicParty } from '../../musicBar/MusicBar';
 import { initCast, localDriver, onCastAvailabilityChanged, onCastSessionEnded, startCast, stopCast } from '../../cast';
 import type { PlaybackDriver } from '../../cast';
+import { clearMediaSession, setMediaSessionActionHandlers, setMediaSessionMetadata, setMediaSessionNextAction, setMediaSessionPlaybackState, setMediaSessionPositionState } from '../../mediaSession';
 
 const TICKS_PER_SECOND = 10000000; // Emby/.NET convention: 1 tick = 100ns
 const DRIFT_TOLERANCE_SECONDS = 1.5;
@@ -149,7 +151,7 @@ export function renderPartyPlayer(root: HTMLElement, params: RouteParams): Clean
     // rendering bug in renderVideoPlayer itself, not just a genuine "party
     // not found", so the stack trace matters here.
     console.error('[watchparty player] failed to open party', err);
-    alert(err.message);
+    showToast(err.message, { variant: 'error' });
     navigate('/home');
   });
 
@@ -196,6 +198,7 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
   const qualitySelect = root.querySelector('#qualitySelect') as HTMLSelectElement;
   const burnInHint = root.querySelector('#burnInHint')!;
   const castBtn = root.querySelector('#castBtn') as HTMLButtonElement;
+  const pipBtn = root.querySelector('#pipBtn') as HTMLButtonElement;
   const fullscreenBtn = root.querySelector('#fullscreenBtn') as HTMLButtonElement;
   const bottomBar = root.querySelector('#bottomBar') as HTMLElement;
   const progressBar = root.querySelector('#progressBar') as HTMLElement;
@@ -203,6 +206,7 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
   const playPauseBtn = root.querySelector('#playPauseBtn') as HTMLButtonElement;
   const muteBtn = root.querySelector('#muteBtn') as HTMLButtonElement;
   const timeLabel = root.querySelector('#timeLabel')!;
+  const skipIntroBtn = root.querySelector('#skipIntroBtn') as HTMLButtonElement;
 
   qualitySelect.innerHTML = QUALITY_PRESETS.map((q) => `<option value="${q.value}">${q.label}</option>`).join('');
 
@@ -225,6 +229,14 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
 
   let isHost = false;
   let hasNextQueued = false;
+  // Set at the top of cleanup() below, which every intentional way of
+  // leaving this route (the "Quitter" button, a sidebar link, browser
+  // back, ...) already runs synchronously before the socket actually
+  // closes - so by the time the async "disconnect" this connection's
+  // own onClose reacts to actually arrives, this is already true for
+  // every one of those. Still false there only means an unprompted
+  // close (most often: a device takeover elsewhere - see onClose below).
+  let leftIntentionally = false;
   let conn: PartyConnection | null = null;
   let hls: HlsInstance | null = null;
   let currentItemId: string | null = null;
@@ -262,6 +274,15 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
   // - see its own comment) can re-render the subtitle picker's host-only
   // gating for burn-in options without a redundant playback-options fetch.
   let lastPlaybackOptions: PlaybackOptionsDto | null = null;
+  // Emby's own native intro/credits detection for currentItemId, if any -
+  // see loadMarkers/updateSkipButton below and CatalogService
+  // .getPlaybackMarkers. Null fields (or this whole thing being null,
+  // while still loading) just mean no skip button, never an error.
+  let currentMarkers: PlaybackMarkersDto | null = null;
+  // One-shot per item - see updateSkipButton's own comment for why this
+  // must NOT re-fire (force the bar open) on every tick for as long as
+  // credits are running.
+  let creditsControlsShown = false;
   // "The player" sendLocalState/applyRemoteState actually read and write -
   // the local <video> by default, swapped for a Chromecast's RemotePlayer
   // while casting (see toggleCast/cast.ts). Casting is available to any
@@ -402,6 +423,7 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
    *  onDriverStateChanged below. */
   function updatePlayPauseBtn() {
     playPauseBtn.innerHTML = activeDriver.paused ? PLAY_BTN_ICON_SVG : PAUSE_BTN_ICON_SVG;
+    setMediaSessionPlaybackState(!activeDriver.paused);
   }
 
   /** #muteBtn - deliberately reads/writes `video.muted` directly, never
@@ -425,6 +447,43 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     const current = activeDriver.currentTime;
     progressFill.style.width = duration > 0 ? `${Math.min(100, (current / duration) * 100)}%` : '0%';
     timeLabel.textContent = duration > 0 ? `${formatDuration(current)} / ${formatDuration(duration)}` : '';
+    setMediaSessionPositionState(duration, current);
+  }
+
+  /**
+   * Shows/hides #skipIntroBtn from activeDriver's current position against
+   * currentMarkers - called continuously (progressTicker, below), same as
+   * updateProgressBar. Host-only: a follower's own seek never broadcasts
+   * (see sendLocalState's own gate), so a local jump here would just get
+   * overwritten by the next correction from the real host - same
+   * reasoning as progressBar being read-only for a follower.
+   *
+   * Credits get no button of their own: #nextBtn already does exactly
+   * "go to the next queued item" and is already shown whenever
+   * hasNextQueued is true (see onItemChanged) - detection's only real
+   * contribution there is making sure it's actually reachable the moment
+   * credits start, by un-minimizing the bar once, rather than requiring
+   * the host to have touched the player recently. The `creditsControlsShown`
+   * guard is what keeps this a one-shot nudge instead of fighting anyone
+   * who deliberately re-minimizes the bar during a long credits scroll.
+   */
+  function updateSkipButton() {
+    if (!isHost || !currentMarkers) {
+      skipIntroBtn.classList.add('hide');
+      return;
+    }
+    const current = activeDriver.currentTime;
+    const { introStartTicks, introEndTicks, creditsStartTicks } = currentMarkers;
+
+    const inIntro = introStartTicks != null && introEndTicks != null
+      && current >= introStartTicks / TICKS_PER_SECOND && current < introEndTicks / TICKS_PER_SECOND;
+    skipIntroBtn.classList.toggle('hide', !inIntro);
+
+    const inCredits = creditsStartTicks != null && current >= creditsStartTicks / TICKS_PER_SECOND;
+    if (inCredits && hasNextQueued && !creditsControlsShown) {
+      creditsControlsShown = true;
+      showControls();
+    }
   }
 
   /** Shared by every discrete play/pause/seek event this player reacts
@@ -469,13 +528,23 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
 
   let isDraggingProgress = false;
 
+  /** Host-only in effect (both call sites already gate on isHost before
+   *  reaching here - the progress bar's own pointerdown handler below,
+   *  and the Media Session seekto action) - this itself just clamps and
+   *  applies, same shape as MusicBar.ts's own seekTo. */
+  function seekTo(seconds: number) {
+    const duration = activeDriver.duration;
+    if (!duration) return;
+    activeDriver.currentTime = Math.min(Math.max(0, seconds), duration);
+    onDriverStateChanged();
+  }
+
   function seekFromPointerEvent(e: PointerEvent) {
     const duration = activeDriver.duration;
     if (!duration) return;
     const rect = progressBar.getBoundingClientRect();
     const fraction = Math.min(1, Math.max(0, (e.clientX - rect.left) / rect.width));
-    activeDriver.currentTime = fraction * duration;
-    onDriverStateChanged();
+    seekTo(fraction * duration);
   }
 
   // Host-only (checked here, not just via the readOnly class - that one
@@ -505,6 +574,12 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     updateMuteBtn();
   });
 
+  skipIntroBtn.addEventListener('click', () => {
+    if (currentMarkers?.introEndTicks == null) return;
+    activeDriver.currentTime = currentMarkers.introEndTicks / TICKS_PER_SECOND;
+    onDriverStateChanged();
+  });
+
   // Ticks the seek bar/time label between discrete events - currentTime
   // moves continuously while playing, with no event of its own for
   // "still playing, time passed" the way play/pause/seeked have. Runs
@@ -515,6 +590,7 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
   progressTicker = window.setInterval(() => {
     if (!currentItemId) return;
     updateProgressBar();
+    updateSkipButton();
   }, 500);
   updatePlayPauseBtn();
   updateMuteBtn();
@@ -607,6 +683,7 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     settingsWrap.classList.remove('hide');
     requestToolbar.classList.add('hide'); // the host acts directly - no requests to make once promoted mid-session
     nextBtn.classList.toggle('hide', !hasNextQueued);
+    setMediaSessionNextAction(hasNextQueued ? goToNextItem : null);
     playPauseBtn.classList.remove('hide');
     progressBar.classList.remove('readOnly');
     updateAmbientNotice();
@@ -614,7 +691,10 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     video.addEventListener('play', onDriverStateChanged);
     video.addEventListener('pause', onDriverStateChanged);
     video.addEventListener('seeked', onDriverStateChanged);
-    video.addEventListener('ended', () => { if (hasNextQueued) conn?.next(); });
+    // The last item ending still counts as watched (Emby Played, a static
+    // watch party's progress) - "itemEnded" tells the server so, since
+    // there's no "next" to send for it.
+    video.addEventListener('ended', () => { if (hasNextQueued) conn?.next(); else conn?.itemEnded(); });
     if (!heartbeat) heartbeat = window.setInterval(reportHeartbeat, 3000);
 
     // Burn-in (image) subtitle options are host-only (see
@@ -625,7 +705,7 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     renderSubtitleOptions();
     applyStreamOptionsGating();
 
-    if (notify) alert("L'hôte précédent a quitté la party - tu es maintenant l'hôte.");
+    if (notify) showToast("L'hôte précédent a quitté la party - tu es maintenant l'hôte.");
   }
 
   async function loadTrackOptions(itemId: string) {
@@ -656,6 +736,24 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     }
   }
 
+  /** Emby's own native intro/credits markers for `itemId`, if the library
+   *  it's from has detection enabled and the task has already reached it
+   *  - see CatalogService.getPlaybackMarkers. Reset first, synchronously,
+   *  not just on a fetch failure: without this, the OLD item's markers
+   *  (and skip button) would keep showing for however long this fetch
+   *  takes on the new one. */
+  async function loadMarkers(itemId: string) {
+    currentMarkers = null;
+    skipIntroBtn.classList.add('hide');
+    creditsControlsShown = false;
+    try {
+      currentMarkers = await getPlaybackMarkers(itemId);
+    } catch (err) {
+      console.error('[watchparty player] playback markers failed', err);
+      // Non-fatal, same as loadTrackOptions above - playback works fine with no skip button.
+    }
+  }
+
   /**
    * (Re)builds the subtitle <select> from the last-fetched playback
    * options, called both on a genuine item load and whenever burn-in/
@@ -925,10 +1023,50 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
   });
   updateFullscreenBtn();
 
+  /**
+   * Picture-in-picture - asked for directly, mobile in particular: the
+   * one way to keep watching in a small floating window while switching
+   * to another app, since a phone has no second window/screen to put
+   * this app in the way a desktop might. Feature-detected once at mount,
+   * not live like #castBtn's own onCastAvailabilityChanged - unlike a
+   * Chromecast appearing/disappearing on the network mid-session,
+   * browser support for this is fixed for the lifetime of the page, so
+   * there's nothing to react to after this first check. video itself
+   * needs no new attribute for this to work - unlike disableremoteplayback
+   * (added specifically to suppress Chrome's own auto cast icon), there's
+   * no equivalent auto-injected native PiP control this app needs to
+   * fight with.
+   */
+  if (document.pictureInPictureEnabled && !video.disablePictureInPicture) {
+    pipBtn.classList.remove('hide');
+    pipBtn.addEventListener('click', () => {
+      if (document.pictureInPictureElement) {
+        document.exitPictureInPicture().catch(() => {});
+      } else {
+        video.requestPictureInPicture().catch((err) => {
+          // Can genuinely fail even when supported (no user gesture in
+          // some browsers' stricter reading of that, video not yet
+          // ready) - same "try it, log it, don't crash anything else"
+          // instinct as every other best-effort browser API this app
+          // calls (video.play().catch, requestFullscreen().catch, ...).
+          console.error('[watchparty player] picture-in-picture failed', err);
+        });
+      }
+    });
+    // Reflects state via the same [aria-pressed] treatment #castBtn
+    // uses (see Player.css's .fsBtn[aria-pressed="true"]) - covers the
+    // browser's own PiP window being closed directly (its native close
+    // button, or the OS), not just this button's own click.
+    video.addEventListener('enterpictureinpicture', () => pipBtn.setAttribute('aria-pressed', 'true'));
+    video.addEventListener('leavepictureinpicture', () => pipBtn.setAttribute('aria-pressed', 'false'));
+  }
+
   async function onItemChanged(msg: ItemChangedMsg) {
     itemTitleEl.textContent = msg.itemName || '';
+    setMediaSessionMetadata(msg.itemName || '', '', '', `/api/catalog/image/${msg.itemId}`);
     hasNextQueued = !!msg.hasNext;
     nextBtn.classList.toggle('hide', !(isHost && hasNextQueued));
+    setMediaSessionNextAction(isHost && hasNextQueued ? goToNextItem : null);
     // A new item's own stream indices/subtitle pick have nothing to do
     // with the old one's - PartyService.advanceQueue already resets this
     // server-side too (see its own comment); this just keeps this client
@@ -940,6 +1078,7 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     burnInAudioIndex = null;
     textSubtitleIndex = null;
     streamAudioIndex = null;
+    loadMarkers(msg.itemId); // not awaited - never needed before playback can start, see loadVideo below
     await loadTrackOptions(msg.itemId);
     loadVideo(msg.itemId, 0, true);
   }
@@ -1075,22 +1214,42 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
   // cooldown (mirroring the server's own independent per-request
   // throttle in SocketGateway) purely so a rapid double-click doesn't
   // even bother emitting the second request.
-  requestPauseBtn.addEventListener('click', () => {
+  function requestPause() {
     const now = Date.now();
     if (now < pauseRequestCooldownUntil || !conn) return;
     pauseRequestCooldownUntil = now + REQUEST_COOLDOWN_MS;
     conn.requestPause();
-  });
+  }
 
-  requestResumeBtn.addEventListener('click', () => {
+  function requestResume() {
     const now = Date.now();
     if (now < resumeRequestCooldownUntil || !conn) return;
     resumeRequestCooldownUntil = now + REQUEST_COOLDOWN_MS;
     conn.requestResume();
-  });
+  }
+
+  requestPauseBtn.addEventListener('click', requestPause);
+  requestResumeBtn.addEventListener('click', requestResume);
+
+  function goToNextItem() {
+    conn?.next();
+  }
 
   async function init() {
     itemTitleEl.textContent = party.itemName || '';
+    setMediaSessionMetadata(party.itemName || '', '', '', `/api/catalog/image/${party.itemId}`);
+    // Play/pause/seek are wired exactly once - see setMediaSessionActionHandlers'
+    // own comment for why they never need re-wiring on a host handoff.
+    // "next" isn't included here: unlike play/pause (always meaningful,
+    // just routed differently for a follower - see requestPause/Resume
+    // above), a *registered* nexttrack handler is what makes Windows show
+    // the control at all, so it has to track hasNextQueued/isHost the
+    // same way #nextBtn's own visibility does - see becomeHost/onItemChanged.
+    setMediaSessionActionHandlers({
+      onPlay: () => { if (isHost) activeDriver.play(); else requestResume(); },
+      onPause: () => { if (isHost) activeDriver.pause(); else requestPause(); },
+      onSeek: (seconds) => { if (isHost) seekTo(seconds); }
+    });
     hasNextQueued = !!party.hasNext;
     updateAmbientNotice();
     requestToolbar.classList.toggle('hide', party.youAreHost);
@@ -1102,8 +1261,22 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
     // image-subtitle option as disabled, as if they were a follower.
     if (party.youAreHost) becomeHost(false);
 
+    loadMarkers(party.itemId); // not awaited - see onItemChanged's own comment
     await loadTrackOptions(party.itemId);
-    loadVideo(party.itemId, 0, false);
+    // Unlike onItemChanged's own loadVideo(..., 0, ...) - genuinely correct
+    // there since a fresh item has no position yet - mounting mid-party
+    // (a joining guest, or the host's own page reload) must NOT hardcode 0:
+    // the party's shared Emby transcode (PartyStreamService) is keyed by
+    // partyId alone, one PlaySessionId for every member, so a hls.js
+    // instance requesting segments from 0 against a session that already
+    // progressed well past that forces Emby to seek/restart the shared
+    // transcode - stalling it for every other member, host included, right
+    // as the newcomer joins. Seeding from the host's last-reported position
+    // (already in party.members, sent to every mount) lands the first
+    // segment request near where the shared session already is instead.
+    const hostMember = party.members.find((m) => m.isHost);
+    const initialResumeSeconds = hostMember ? hostMember.positionTicks / TICKS_PER_SECOND : 0;
+    loadVideo(party.itemId, initialResumeSeconds, false);
 
     conn = connectParty(partyId, {
       onMembers: renderMembers,
@@ -1127,12 +1300,28 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
         if (takeOver) conn?.confirmDeviceTakeover();
         else navigate('/home');
       },
-      onError: (message) => alert(message),
-      onClose: () => {}
+      onError: (message) => showToast(message, { variant: 'error' }),
+      // Fires for every disconnect, intentional or not - leftIntentionally
+      // is already true by the time this runs for any of those (see its
+      // own comment), so still false here means an unprompted close, most
+      // often a device takeover elsewhere (SocketGateway's "join" handler)
+      // - without this, the video/hls.js instance just kept running
+      // forever on the old device, on a conn that was actually already
+      // dead underneath it, reported directly as "both devices end up on
+      // the session, controls never transfer." navigate() runs this same
+      // route's cleanup() below, which is now safe to do even though the
+      // party already moved on - leaveParty's own deviceId check (see
+      // api/party.ts) makes its REST call a no-op for a stale device
+      // instead of ending the CURRENT device's membership by mistake.
+      onClose: () => {
+        if (leftIntentionally) return;
+        showToast('Connexion à la party interrompue.', { variant: 'error' });
+        navigate('/home');
+      }
     });
   }
 
-  nextBtn.addEventListener('click', () => { conn?.next(); });
+  nextBtn.addEventListener('click', goToNextItem);
   (root.querySelector('#leaveBtn') as HTMLButtonElement).addEventListener('click', () => navigate('/home'));
 
   init();
@@ -1142,11 +1331,13 @@ function renderVideoPlayer(root: HTMLElement, partyId: string, party: PartyPubli
   // other way (sidebar link, browser back, ...). This is the fix for the
   // actual leak: previously, only the "Quitter" button ran any of this.
   return function cleanup() {
+    leftIntentionally = true;
     if (heartbeat) clearInterval(heartbeat);
     if (progressTicker) clearInterval(progressTicker);
     if (requestBannerTimer) clearTimeout(requestBannerTimer);
     clearControlsHideTimer();
     if (hls) hls.destroy();
+    clearMediaSession();
     document.removeEventListener('click', onDocumentClick);
     document.removeEventListener('fullscreenchange', onFullscreenChange);
     playerWrap.removeEventListener('pointermove', showControls);

client/src/views/playlist/Playlist.css

@@ -25,8 +25,9 @@
 
 .playlistActions {
   display: flex;
+  flex-wrap: wrap;
   align-items: center;
-  gap: 16px;
+  gap: 12px 16px;
   margin-top: 4px;
 }
 

client/src/views/playlist/Playlist.html

@@ -6,6 +6,7 @@
     <p class="hint" id="playlistMeta"></p>
     <div class="playlistActions">
       <button id="launchBtn">Lancer cette playlist</button>
+      <button class="hide" id="createStaticBtn">Créer une lounge party</button>
       <a class="linklike" id="embyLink" target="_blank" rel="noopener">Voir sur Emby</a>
     </div>
   </div>

client/src/views/playlist/Playlist.ts

@@ -2,11 +2,13 @@ import './Playlist.css';
 import html from './Playlist.html';
 import { getItem, getPlaylistItems } from '../../api/embyApi';
 import { createParty } from '../../api/party';
+import { wireCreateStaticButton } from '../staticParty/createStaticButton';
 import { joinMusicParty } from '../../musicBar/MusicBar';
 import { navigate } from '../../router';
 import type { RouteParams } from '../../router';
 import { escapeHtml, formatDuration } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
+import { showToast } from '../../toast';
 import type { ItemDto } from '../../types';
 
 const TICKS_PER_SECOND = 10000000; // Emby/.NET convention: 1 tick = 100ns, same as everywhere else this app touches durations
@@ -55,6 +57,15 @@ export async function renderPlaylist(root: HTMLElement, params: RouteParams): Pr
     return;
   }
 
+  // Video playlists only - a static watch party has no music equivalent
+  // (the server refuses one too). Same "first item decides" rule as
+  // CatalogService.splitPlaylistByMediaType.
+  if (items[0]!.type !== 'Audio') {
+    const createStaticBtn = root.querySelector('#createStaticBtn') as HTMLButtonElement;
+    createStaticBtn.classList.remove('hide');
+    wireCreateStaticButton(createStaticBtn, () => playlistId);
+  }
+
   listEl.innerHTML = items.map((item, i) => {
     const meta = item.overview || [item.artistName, item.albumName].filter(Boolean).join(' · ');
     const duration = item.durationTicks ? formatDuration(item.durationTicks / TICKS_PER_SECOND) : '';
@@ -93,7 +104,7 @@ export async function renderPlaylist(root: HTMLElement, params: RouteParams): Pr
         navigate(`/party/${party.partyId}`);
       }
     } catch (err) {
-      alert((err as Error).message);
+      showToast((err as Error).message, { variant: 'error' });
       btn.disabled = false;
       btn.textContent = idleLabel;
     }

client/src/views/series/Series.css

@@ -17,6 +17,20 @@
 
 .seriesPoster.noImage { visibility: hidden; }
 
+.seriesActions,
+.seasonActions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 12px 16px;
+  margin-top: 8px;
+}
+
+/* The selected season's own launch buttons, between the tabs and its
+   episodes. */
+.seasonActions { margin: 0 0 16px; }
+.seasonActions button { padding: 8px 14px; font-size: 13px; }
+
 @media (max-width: 600px) {
   .seriesHeader { flex-direction: column; }
   .seriesPoster { width: 120px; }

client/src/views/series/Series.html

@@ -4,8 +4,16 @@
   <div class="seriesInfo">
     <h1 id="seriesTitle"></h1>
     <p class="seriesOverview hide" id="seriesOverview"></p>
+    <div class="seriesActions">
+      <button id="launchSeriesBtn">Lancer toute la série</button>
+      <button class="secondaryBtn" id="createStaticBtn">Créer une lounge party</button>
       <a class="linklike" id="embyLink" target="_blank" rel="noopener">Voir sur Emby</a>
     </div>
+  </div>
 </div>
 <nav id="seasonTabs" class="tabs"></nav>
+<div class="seasonActions hide" id="seasonActions">
+  <button id="launchSeasonBtn">Lancer cette saison</button>
+  <button class="secondaryBtn" id="createSeasonStaticBtn">Lounge party de cette saison</button>
+</div>
 <div id="episodeList" class="episodeList"><p class="hint">Chargement...</p></div>

client/src/views/series/Series.ts

@@ -2,10 +2,12 @@ import './Series.css';
 import html from './Series.html';
 import { getItem, getSeriesEpisodes, getSeriesSeasons } from '../../api/embyApi';
 import { createParty } from '../../api/party';
+import { wireCreateStaticButton } from '../staticParty/createStaticButton';
 import { navigate } from '../../router';
 import type { RouteParams } from '../../router';
 import { escapeHtml } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
+import { showToast } from '../../toast';
 import type { ItemDto, SeasonDto } from '../../types';
 
 export async function renderSeries(root: HTMLElement, params: RouteParams): Promise<void> {
@@ -34,11 +36,25 @@ export async function renderSeries(root: HTMLElement, params: RouteParams): Prom
   }
   (root.querySelector('#embyLink') as HTMLAnchorElement).href = series.embyUrl;
 
+  // Whole series: a watch party over every season from S1E1, or a lounge
+  // party over the same (see the server's seriesQueueFrom).
+  wireLaunchButton(root.querySelector('#launchSeriesBtn') as HTMLButtonElement, () => seriesId);
+  wireCreateStaticButton(root.querySelector('#createStaticBtn') as HTMLButtonElement, () => seriesId);
+
   if (!seasons.length) {
+    (root.querySelector('#launchSeriesBtn') as HTMLButtonElement).disabled = true;
+    (root.querySelector('#createStaticBtn') as HTMLButtonElement).disabled = true;
     root.querySelector('#episodeList')!.innerHTML = '<p class="hint">Aucune saison trouvée.</p>';
     return;
   }
 
+  // Just the selected season - both buttons read whichever tab is active
+  // at click time, so they're wired once rather than per tab switch.
+  let selectedSeasonId = seasons[0]!.id;
+  root.querySelector('#seasonActions')!.classList.remove('hide');
+  wireLaunchButton(root.querySelector('#launchSeasonBtn') as HTMLButtonElement, () => selectedSeasonId);
+  wireCreateStaticButton(root.querySelector('#createSeasonStaticBtn') as HTMLButtonElement, () => selectedSeasonId);
+
   const tabsEl = root.querySelector('#seasonTabs')!;
   tabsEl.innerHTML = seasons
     .map((s, i) => `<button class="tab${i === 0 ? ' active' : ''}" data-season-id="${s.id}">${escapeHtml(s.name)}</button>`)
@@ -49,13 +65,35 @@ export async function renderSeries(root: HTMLElement, params: RouteParams): Prom
       if (tab.classList.contains('active')) return;
       tabsEl.querySelectorAll('.tab').forEach((t) => t.classList.remove('active'));
       tab.classList.add('active');
-      loadEpisodes(root, seriesId, tab.dataset.seasonId as string);
+      selectedSeasonId = tab.dataset.seasonId as string;
+      loadEpisodes(root, seriesId, selectedSeasonId);
     });
   });
 
   loadEpisodes(root, seriesId, seasons[0]!.id);
 }
 
+/**
+ * A button that launches a watch party over whatever `itemId()` returns
+ * at click time - the series (every season) or the selected season (see
+ * the server's POST /api/parties Series/Season branches) - then opens it.
+ */
+function wireLaunchButton(btn: HTMLButtonElement, itemId: () => string): void {
+  const idleLabel = btn.textContent || '';
+  btn.addEventListener('click', () => {
+    btn.disabled = true;
+    btn.textContent = 'Démarrage...';
+    createParty(itemId())
+      .then((party) => navigate(`/party/${party.partyId}`))
+      .catch((err: unknown) => {
+        console.error('[series] launch failed', err);
+        showToast((err as Error).message, { variant: 'error' });
+        btn.disabled = false;
+        btn.textContent = idleLabel;
+      });
+  });
+}
+
 async function loadEpisodes(root: HTMLElement, seriesId: string, seasonId: string): Promise<void> {
   const listEl = root.querySelector('#episodeList')!;
   listEl.innerHTML = LOADING_HINT;
@@ -95,7 +133,7 @@ async function loadEpisodes(root: HTMLElement, seriesId: string, seasonId: strin
         const party = await createParty(btn.dataset.itemId as string);
         navigate(`/party/${party.partyId}`);
       } catch (err) {
-        alert((err as Error).message);
+        showToast((err as Error).message, { variant: 'error' });
         btn.disabled = false;
         btn.textContent = 'Lancer une watch party';
       }

client/src/views/staticParties/StaticParties.css

@@ -0,0 +1,81 @@
+/* ---- "Lounge parties" tab: one card per static party ---- */
+
+.staticGrid {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
+  gap: 14px;
+}
+
+/* The whole card is the link to /static/:id. */
+.staticCard {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+  background: var(--bg-header);
+  border-radius: 10px;
+  padding: 12px;
+  color: inherit;
+  text-decoration: none;
+}
+
+.staticCard:hover { background: #2b252e; }
+
+.staticCard img {
+  width: 60px;
+  height: 90px;
+  object-fit: cover;
+  border-radius: 6px;
+  background: var(--panel);
+  flex-shrink: 0;
+}
+
+.staticCard img.noImage { visibility: hidden; }
+
+.staticCardInfo {
+  flex: 1;
+  min-width: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+}
+
+.staticCardInfo strong { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
+.staticCardInfo .hint { margin: 0; }
+
+.staticCardNext {
+  font-size: 12px;
+  color: var(--muted);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.staticCardBar {
+  height: 4px;
+  border-radius: 2px;
+  background: var(--panel);
+  overflow: hidden;
+}
+
+.staticCardBar > div { height: 100%; background: var(--accent); }
+
+.staticCardLive {
+  color: var(--accent-bright);
+  font-size: 12px;
+  font-weight: 600;
+}
+
+.staticCardMissed {
+  flex-shrink: 0;
+  align-self: flex-start;
+  padding: 4px 10px;
+  border-radius: 12px;
+  background: var(--danger);
+  color: #fff;
+  font-size: 12px;
+  font-weight: 600;
+}
+
+@media (max-width: 400px) {
+  .staticGrid { grid-template-columns: 1fr; }
+}

client/src/views/staticParties/StaticParties.html

@@ -0,0 +1,9 @@
+<div class="pageHeader">
+  <h1>Lounge parties</h1>
+</div>
+<p class="hint">
+  Une série ou une playlist regardée en groupe sur plusieurs séances : la progression du groupe
+  et celle de chacun sont gardées en mémoire. Pour en créer une, ouvre une série ou une playlist
+  vidéo et choisis « Créer une lounge party ».
+</p>
+<div class="staticGrid" id="staticGrid"></div>

client/src/views/staticParties/StaticParties.ts

@@ -0,0 +1,77 @@
+import './StaticParties.css';
+import html from './StaticParties.html';
+import { connectLobby } from '../../api/party';
+import { listStaticParties } from '../../api/staticParty';
+import { escapeHtml } from '../../tiles';
+import { SOURCE_LABELS } from '../staticParty/StaticParty';
+import { LOADING_HINT } from '../../loading';
+import type { StaticPartySummaryDto } from '../../types';
+
+/**
+ * Route `/static` - the "Lounge parties" tab: every static
+ * watch party, kept apart from the home page's classic live parties
+ * (whose lobby list leaves static sessions out - see Home.ts).
+ *
+ * A REST list, re-fetched whenever the set of live static-party sessions
+ * in the lobby changes (a session starting or ending is what moves a
+ * card's "séance en cours"/progress state). Not on every lobby snapshot:
+ * those also fire on every pause/join, and each list fetch reads Emby
+ * once per static party (see server/src/index.ts's syncStaticSource).
+ */
+export function renderStaticParties(root: HTMLElement): () => void {
+  root.innerHTML = html;
+  const grid = root.querySelector('#staticGrid') as HTMLElement;
+  grid.innerHTML = LOADING_HINT;
+
+  let sessionsKey: string | null = null;
+  const lobby = connectLobby((parties) => {
+    const key = parties.map((p) => p.staticPartyId).filter(Boolean).sort().join(',');
+    if (key === sessionsKey) return;
+    sessionsKey = key;
+    load(grid);
+  });
+
+  // Same leak-prevention contract as Home.ts: the router calls this before
+  // rendering the next view.
+  return function cleanup() {
+    lobby.disconnect();
+  };
+}
+
+/** Fetches and renders every static party into `grid`. */
+function load(grid: HTMLElement): void {
+  listStaticParties()
+    .then((parties) => {
+      if (!grid.isConnected) return; // navigated away mid-flight
+      render(grid, parties);
+    })
+    .catch((err: unknown) => {
+      console.error('[staticParties] list failed to load', err);
+      if (grid.isConnected) grid.innerHTML = `<p class="error">${escapeHtml((err as Error).message)}</p>`;
+    });
+}
+
+/** One card per static party: progress, next item, the viewer's missed
+ *  count, and whether a session is running right now. */
+function render(grid: HTMLElement, parties: StaticPartySummaryDto[]): void {
+  if (!parties.length) {
+    grid.innerHTML = '<p class="hint">Aucune lounge party pour le moment.</p>';
+    return;
+  }
+  grid.innerHTML = parties.map((p) => {
+    const percent = p.itemCount ? Math.round((p.groupWatchedCount / p.itemCount) * 100) : 0;
+    return `
+      <a class="staticCard" href="#/static/${escapeHtml(p.id)}">
+        <img src="${escapeHtml(p.imageUrl)}" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
+        <div class="staticCardInfo">
+          <strong>${escapeHtml(p.name)}</strong>
+          <span class="hint">${SOURCE_LABELS[p.sourceType]} · ${p.groupWatchedCount}/${p.itemCount} vus · ${p.memberCount} membre${p.memberCount > 1 ? 's' : ''}</span>
+          <div class="staticCardBar"><div style="width:${percent}%"></div></div>
+          ${p.livePartyId
+            ? '<span class="staticCardLive">● Séance en cours</span>'
+            : `<span class="staticCardNext">${p.nextItemName ? `Prochain : ${escapeHtml(p.nextItemName)}` : 'Le groupe a tout vu.'}</span>`}
+        </div>
+        ${p.missedCount ? `<span class="staticCardMissed" title="Éléments manqués">${p.missedCount} manqué${p.missedCount > 1 ? 's' : ''}</span>` : ''}
+      </a>`;
+  }).join('');
+}

client/src/views/staticParty/StaticParty.css

@@ -0,0 +1,138 @@
+/* ---- Static (persistent) watch party page ----
+   .seriesInfo/.episodeList/.episodeRow/.episodeInfo are reused as-is from
+   views/series/Series.css (always in the bundle - same precedent as
+   Playlist.css/Album.css). Only what's specific to this page lives here. */
+
+.staticHeader {
+  display: flex;
+  gap: 20px;
+  margin-bottom: 28px;
+}
+
+.staticCover {
+  width: 160px;
+  aspect-ratio: 2 / 3;
+  object-fit: cover;
+  border-radius: 8px;
+  background: var(--panel);
+  flex-shrink: 0;
+}
+
+.staticCover.noImage { visibility: hidden; }
+
+.staticBadge {
+  display: inline-block;
+  font-size: 11px;
+  font-weight: 700;
+  letter-spacing: .06em;
+  text-transform: uppercase;
+  color: var(--accent-bright);
+  margin-bottom: 6px;
+}
+
+.staticMeta { margin: 6px 0 10px; }
+
+.staticProgress {
+  height: 6px;
+  max-width: 360px;
+  border-radius: 3px;
+  background: var(--panel);
+  overflow: hidden;
+}
+
+.staticProgressFill {
+  height: 100%;
+  width: 0;
+  background: var(--accent);
+  transition: width .3s;
+}
+
+.staticNext { margin: 10px 0 14px; font-size: 14px; }
+
+.staticActions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 12px 16px;
+}
+
+/* A quieter variant of the global green button - for actions next to a
+   primary one (joining, catching up) that shouldn't compete with it. */
+.secondaryBtn {
+  background: var(--panel);
+  color: var(--text);
+}
+
+.secondaryBtn:hover { background: #333; }
+
+.staticSectionHead {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  flex-wrap: wrap;
+  gap: 12px;
+  margin-bottom: 8px;
+}
+
+.staticSectionHead h2 { margin: 0; }
+
+.staticCount {
+  display: inline-block;
+  min-width: 22px;
+  padding: 1px 7px;
+  margin-left: 6px;
+  border-radius: 11px;
+  background: var(--danger);
+  color: #fff;
+  font-size: 12px;
+  text-align: center;
+}
+
+.staticBulkActions { display: flex; flex-wrap: wrap; gap: 8px; }
+.staticBulkActions button,
+.staticRowActions button { padding: 8px 12px; font-size: 13px; }
+
+.staticMissed .episodeRow { border-left: 3px solid var(--danger); }
+
+.staticCheck {
+  width: 18px;
+  height: 18px;
+  margin: 0;
+  flex-shrink: 0;
+  accent-color: var(--accent);
+}
+
+.staticRowActions { display: flex; flex-wrap: wrap; gap: 8px; flex-shrink: 0; }
+
+/* Group-progress list: what the group has seen fades back, the next item
+   stands out. */
+.episodeRow.isWatched { opacity: .55; }
+.episodeRow.isNext { outline: 2px solid var(--accent); }
+
+.staticState {
+  flex-shrink: 0;
+  font-size: 12px;
+  font-weight: 600;
+  color: var(--muted);
+  text-align: right;
+}
+
+.staticState .mine { display: block; color: var(--accent-bright); font-weight: 400; }
+.episodeRow.isNext .staticState { color: var(--accent-bright); }
+
+.staticMembers { display: flex; flex-wrap: wrap; gap: 8px; }
+
+.staticMember {
+  background: var(--bg-header);
+  border-radius: 16px;
+  padding: 6px 12px;
+  font-size: 13px;
+}
+
+.staticMember .hint { margin: 0 0 0 6px; font-size: 12px; }
+
+@media (max-width: 600px) {
+  .staticHeader { flex-direction: column; }
+  .staticCover { width: 120px; }
+  .staticRowActions { flex-basis: 100%; order: 4; }
+}

client/src/views/staticParty/StaticParty.html

@@ -0,0 +1,39 @@
+<button class="linklike" id="back">&larr; Retour</button>
+<div class="staticHeader">
+  <img class="staticCover" id="staticCover" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
+  <div class="seriesInfo">
+    <span class="staticBadge">Lounge party</span>
+    <h1 id="staticTitle"></h1>
+    <p class="hint staticMeta" id="staticMeta"></p>
+    <div class="staticProgress" aria-hidden="true"><div class="staticProgressFill" id="staticProgressFill"></div></div>
+    <p class="staticNext" id="staticNext"></p>
+    <div class="staticActions">
+      <button id="sessionBtn">Lancer la séance</button>
+      <button class="secondaryBtn hide" id="joinBtn">Rejoindre cette lounge party</button>
+      <button class="linklike hide" id="leaveBtn">Quitter</button>
+      <button class="linklike hide" id="deleteBtn">Supprimer</button>
+    </div>
+  </div>
+</div>
+
+<section class="section staticMissed" id="missedSection" hidden>
+  <div class="staticSectionHead">
+    <h2>Tu as manqué <span class="staticCount" id="missedCount"></span></h2>
+    <div class="staticBulkActions">
+      <button class="secondaryBtn" id="catchUpSoloBtn">Rattraper en solo</button>
+      <button class="secondaryBtn" id="catchUpPartyBtn">Lancer une watch party de rattrapage</button>
+    </div>
+  </div>
+  <p class="hint">Décoche ce que tu ne veux pas rattraper tout de suite.</p>
+  <div class="episodeList" id="missedList"></div>
+</section>
+
+<section class="section">
+  <h2>Membres</h2>
+  <div class="staticMembers" id="memberList"></div>
+</section>
+
+<section class="section">
+  <h2>Progression du groupe</h2>
+  <div class="episodeList" id="itemList"></div>
+</section>

client/src/views/staticParty/StaticParty.ts

@@ -0,0 +1,227 @@
+import './StaticParty.css';
+import html from './StaticParty.html';
+import {
+  deleteStaticParty,
+  getStaticParty,
+  joinStaticParty,
+  leaveStaticParty,
+  markStaticItemWatched,
+  startCatchUp,
+  startStaticSession
+} from '../../api/staticParty';
+import { navigate } from '../../router';
+import type { RouteParams } from '../../router';
+import { escapeHtml } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
+import { showToast } from '../../toast';
+import type { StaticPartyDetailDto, StaticPartyItemDto } from '../../types';
+
+/** How each lounge party source is named in the UI - shared with the
+ *  "Lounge parties" tab (views/staticParties). */
+export const SOURCE_LABELS: Record<StaticPartyDetailDto['sourceType'], string> = {
+  series: 'Série',
+  season: 'Saison',
+  playlist: 'Playlist'
+};
+
+/**
+ * Route `/static/:id` - one static (persistent) watch party: the group's
+ * progress through the whole series/playlist, its members, and - the
+ * point of the feature - what *you* missed, with ways to catch up (alone,
+ * or as a watch party others can join) or mark things as already seen.
+ * Launching the group's session hands off to the normal player
+ * (`/party/:id`) - a session is an ordinary party server-side. See
+ * server/src/services/StaticPartyService.ts and spec/static-watch-party.md.
+ */
+export async function renderStaticParty(root: HTMLElement, params: RouteParams): Promise<void> {
+  const staticId = params.id as string;
+  root.innerHTML = LOADING_HINT;
+
+  let detail: StaticPartyDetailDto;
+  try {
+    detail = await getStaticParty(staticId);
+  } catch (err) {
+    console.error('[staticParty] load failed', staticId, err);
+    root.innerHTML = `<p class="error">${escapeHtml((err as Error).message || 'Impossible de charger cette lounge party.')}</p>`;
+    return;
+  }
+
+  root.innerHTML = html;
+  root.querySelector('#back')!.addEventListener('click', () => history.back());
+  wireActions(root, staticId);
+  render(root, detail);
+}
+
+/** Re-fetches and re-renders in place - after any action that changed
+ *  progress or membership. */
+async function reload(root: HTMLElement, staticId: string): Promise<void> {
+  try {
+    const detail = await getStaticParty(staticId);
+    if (!root.querySelector('#staticTitle')) return; // navigated away mid-flight
+    render(root, detail);
+  } catch (err) {
+    console.error('[staticParty] reload failed', staticId, err);
+    showToast((err as Error).message, { variant: 'error' });
+  }
+}
+
+/** Fills every part of the page from `detail`. */
+function render(root: HTMLElement, detail: StaticPartyDetailDto): void {
+  (root.querySelector('#staticCover') as HTMLImageElement).src = detail.imageUrl;
+  root.querySelector('#staticTitle')!.textContent = detail.name;
+  const sourceLabel = SOURCE_LABELS[detail.sourceType];
+  root.querySelector('#staticMeta')!.textContent =
+    `${sourceLabel} · ${detail.groupWatchedCount}/${detail.itemCount} vus par le groupe · ${detail.memberCount} membre${detail.memberCount > 1 ? 's' : ''}`;
+  const percent = detail.itemCount ? Math.round((detail.groupWatchedCount / detail.itemCount) * 100) : 0;
+  (root.querySelector('#staticProgressFill') as HTMLElement).style.width = `${percent}%`;
+  root.querySelector('#staticNext')!.innerHTML = detail.nextItemName
+    ? `Prochain : <strong>${escapeHtml(detail.nextItemName)}</strong>`
+    : '<strong>Le groupe a tout vu.</strong>';
+
+  const sessionBtn = root.querySelector('#sessionBtn') as HTMLButtonElement;
+  sessionBtn.textContent = detail.livePartyId ? 'Rejoindre la séance en cours' : 'Lancer la séance';
+  sessionBtn.disabled = !detail.livePartyId && !detail.nextItemName;
+  root.querySelector('#joinBtn')!.classList.toggle('hide', detail.youAreMember);
+  root.querySelector('#leaveBtn')!.classList.toggle('hide', !detail.youAreMember || detail.youAreCreator);
+  root.querySelector('#deleteBtn')!.classList.toggle('hide', !detail.youAreCreator);
+
+  renderMissed(root, detail);
+  renderMembers(root, detail);
+  renderItems(root, detail);
+}
+
+/** "Tu as manqué" - hidden entirely when there's nothing to catch up on. */
+function renderMissed(root: HTMLElement, detail: StaticPartyDetailDto): void {
+  const section = root.querySelector('#missedSection') as HTMLElement;
+  const missed = new Set(detail.missedItemIds);
+  const items = detail.items.filter((i) => missed.has(i.itemId));
+  section.hidden = !items.length;
+  root.querySelector('#missedCount')!.textContent = String(items.length);
+  root.querySelector('#missedList')!.innerHTML = items.map((item) => `
+    <div class="episodeRow">
+      <input type="checkbox" class="staticCheck" data-item-id="${escapeHtml(item.itemId)}" checked aria-label="Inclure dans le rattrapage" />
+      <img src="${escapeHtml(item.itemImageUrl)}" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
+      <div class="episodeInfo"><strong>${escapeHtml(item.itemName)}</strong></div>
+      <div class="staticRowActions">
+        <button class="secondaryBtn soloOneBtn" data-item-id="${escapeHtml(item.itemId)}">Regarder en solo</button>
+        <button class="secondaryBtn markWatchedBtn" data-item-id="${escapeHtml(item.itemId)}">Marquer comme vu</button>
+      </div>
+    </div>`).join('');
+}
+
+/** One chip per member, with how many items they've watched. */
+function renderMembers(root: HTMLElement, detail: StaticPartyDetailDto): void {
+  root.querySelector('#memberList')!.innerHTML = detail.members.length
+    ? detail.members.map((m) => `
+      <span class="staticMember">${escapeHtml(m.userName)}${m.isCreator ? ' ★' : ''}<span class="hint">${m.watchedCount}/${detail.itemCount}</span></span>`).join('')
+    : '<p class="hint">Aucun membre pour le moment.</p>';
+}
+
+/** The whole item list, with the group's state and the viewer's own. */
+function renderItems(root: HTMLElement, detail: StaticPartyDetailDto): void {
+  root.querySelector('#itemList')!.innerHTML = detail.items.map((item, i) => `
+    <div class="episodeRow${item.groupState === 'watched' ? ' isWatched' : ''}${item.groupState === 'next' ? ' isNext' : ''}">
+      <img src="${escapeHtml(item.itemImageUrl)}" alt="" loading="lazy" onerror="this.classList.add('noImage')" />
+      <div class="episodeInfo"><strong>${i + 1}. ${escapeHtml(item.itemName)}</strong></div>
+      <span class="staticState">${stateLabel(item)}${item.viewerWatched ? '<span class="mine">✓ vu par toi</span>' : ''}</span>
+    </div>`).join('');
+}
+
+/** The group-state label for one item. */
+function stateLabel(item: StaticPartyItemDto): string {
+  if (item.groupState === 'watched') return 'Vu par le groupe';
+  if (item.groupState === 'next') return 'Prochain';
+  return 'À venir';
+}
+
+/**
+ * Wires every button once - lists are re-rendered on reload, so row
+ * buttons use one delegated listener on their container rather than
+ * per-row listeners re-added on every render.
+ */
+function wireActions(root: HTMLElement, staticId: string): void {
+  const sessionBtn = root.querySelector('#sessionBtn') as HTMLButtonElement;
+  sessionBtn.addEventListener('click', () => {
+    runBusy(sessionBtn, async () => {
+      const { partyId } = await startStaticSession(staticId);
+      navigate(`/party/${partyId}`);
+    });
+  });
+
+  const joinBtn = root.querySelector('#joinBtn') as HTMLButtonElement;
+  joinBtn.addEventListener('click', () => {
+    runBusy(joinBtn, async () => {
+      await joinStaticParty(staticId);
+      showToast('Tu fais maintenant partie de cette lounge party.');
+      await reload(root, staticId);
+    });
+  });
+
+  const leaveBtn = root.querySelector('#leaveBtn') as HTMLButtonElement;
+  leaveBtn.addEventListener('click', () => {
+    if (!confirm('Quitter cette lounge party ? Ta progression y sera oubliée.')) return;
+    runBusy(leaveBtn, async () => {
+      await leaveStaticParty(staticId);
+      await reload(root, staticId);
+    });
+  });
+
+  const deleteBtn = root.querySelector('#deleteBtn') as HTMLButtonElement;
+  deleteBtn.addEventListener('click', () => {
+    if (!confirm('Supprimer cette lounge party pour tout le monde ? La progression de chacun sera perdue.')) return;
+    runBusy(deleteBtn, async () => {
+      await deleteStaticParty(staticId);
+      showToast('Lounge party supprimée.');
+      navigate('/static');
+    });
+  });
+
+  const catchUp = (btn: HTMLButtonElement, mode: 'solo' | 'party') => {
+    const itemIds = Array.from(root.querySelectorAll<HTMLInputElement>('#missedList .staticCheck'))
+      .filter((c) => c.checked)
+      .map((c) => c.dataset.itemId as string);
+    if (!itemIds.length) {
+      showToast('Coche au moins un élément à rattraper.', { variant: 'error' });
+      return;
+    }
+    runBusy(btn, async () => {
+      const { partyId } = await startCatchUp(staticId, itemIds, mode);
+      navigate(`/party/${partyId}`);
+    });
+  };
+  const soloBtn = root.querySelector('#catchUpSoloBtn') as HTMLButtonElement;
+  const partyBtn = root.querySelector('#catchUpPartyBtn') as HTMLButtonElement;
+  soloBtn.addEventListener('click', () => catchUp(soloBtn, 'solo'));
+  partyBtn.addEventListener('click', () => catchUp(partyBtn, 'party'));
+
+  root.querySelector('#missedList')!.addEventListener('click', (e) => {
+    const btn = (e.target as HTMLElement).closest<HTMLButtonElement>('button[data-item-id]');
+    if (!btn) return;
+    const itemId = btn.dataset.itemId as string;
+    if (btn.classList.contains('soloOneBtn')) {
+      runBusy(btn, async () => {
+        const { partyId } = await startCatchUp(staticId, [itemId], 'solo');
+        navigate(`/party/${partyId}`);
+      });
+    } else if (btn.classList.contains('markWatchedBtn')) {
+      runBusy(btn, async () => {
+        await markStaticItemWatched(staticId, itemId);
+        await reload(root, staticId);
+      });
+    }
+  });
+}
+
+/** Disables `btn` while `action` runs; a failure is toasted, logged, and
+ *  gives the button back. */
+function runBusy(btn: HTMLButtonElement, action: () => Promise<void>): void {
+  btn.disabled = true;
+  action()
+    .catch((err: unknown) => {
+      console.error('[staticParty] action failed', err);
+      showToast((err as Error).message, { variant: 'error' });
+    })
+    .finally(() => {
+      btn.disabled = false;
+    });
+}

client/src/views/staticParty/createStaticButton.ts

@@ -0,0 +1,31 @@
+import { createStaticParty } from '../../api/staticParty';
+import { navigate } from '../../router';
+import { showToast } from '../../toast';
+
+/**
+ * "Créer une lounge party" - shared by views/series (whole series, or
+ * the selected season) and views/playlist: creates a lounge party over
+ * the source id (a series, a season or a video playlist - the server
+ * decides which, and refuses anything else with a message) and opens its
+ * page. `sourceId` is read at click time, so a caller whose source can
+ * change (the selected season tab) wires the button only once.
+ */
+export function wireCreateStaticButton(btn: HTMLButtonElement, getSourceId: () => string): void {
+  const idleLabel = btn.textContent || '';
+  btn.addEventListener('click', () => {
+    const sourceId = getSourceId();
+    btn.disabled = true;
+    btn.textContent = 'Création...';
+    createStaticParty(sourceId)
+      .then((sp) => {
+        console.info('[staticParty] created', sp.id, 'from', sourceId);
+        navigate(`/static/${sp.id}`);
+      })
+      .catch((err: unknown) => {
+        console.error('[staticParty] create failed', sourceId, err);
+        showToast((err as Error).message, { variant: 'error' });
+        btn.disabled = false;
+        btn.textContent = idleLabel;
+      });
+  });
+}

docker-compose.yml

@@ -8,3 +8,9 @@ services:
       - "3000:3000"
     environment:
       EMBY_SERVER_URL: "https://theater.media.kyuno.fr"
+      # Static (persistent) watch parties are saved here - see
+      # server/src/services/StaticPartyStore.ts. Without the volume below
+      # they'd be lost every time the container is recreated.
+      DATA_DIR: "/data"
+    volumes:
+      - ./data:/data

server/Dockerfile

@@ -46,6 +46,10 @@ COPY --from=build /app/client/dist ./client/dist
 
 WORKDIR /app/server
 ENV PORT=3000
+# Static watch parties' JSON file (StaticPartyStore) - mount a volume here
+# (docker-compose.yml does), or they're lost with the container.
+ENV DATA_DIR=/data
+RUN mkdir -p /data
 EXPOSE 3000
 
 CMD ["node", "dist/index.js"]

server/package.json

@@ -9,7 +9,7 @@
     "start": "node dist/index.js",
     "dev": "tsx watch src/index.ts",
     "typecheck": "tsc -p tsconfig.test.json",
-    "test": "tsx --test test/castTokenService.test.ts test/catalogService.test.ts test/embyClient.test.ts test/musicQueueService.test.ts test/partyService.test.ts test/partyStreamService.test.ts test/playstateService.test.ts test/socketGateway.test.ts test/transcodeService.test.ts"
+    "test": "tsx --test test/castTokenService.test.ts test/catalogService.test.ts test/embyClient.test.ts test/embySessionService.test.ts test/musicQueueService.test.ts test/partyService.test.ts test/partyStreamService.test.ts test/playstateService.test.ts test/socketGateway.test.ts test/staticPartyService.test.ts test/transcodeService.test.ts"
   },
   "engines": {
     "node": ">=18"

server/src/Logger.ts

@@ -66,18 +66,28 @@ export class Logger {
     console.log(`[watchparty:transcode] ${new Date().toISOString()} ${message}`);
   }
 
-  /** The party watch-state sync (index.ts's periodic sweep, and
-   *  PartyService.advanceQueue/MusicQueueService.playNext's own item-
-   *  transition calls - see PlaystateService) - logs every outgoing
-   *  request (method + path, and the POST body for the UserData write)
-   *  and its outcome, not just failures: this is a best-effort
-   *  background sync with nothing else watching it, so `docker logs |
-   *  grep watchparty:playstate` needs to be enough on its own to see
-   *  exactly what was sent and whether Emby accepted it, without cross-
-   *  referencing `emby` above. Safe to log in full here (unlike `stream`
-   *  above) - the real embyToken travels as a header, never logged, and
-   *  PlaystateService's own tests confirm it never leaks into these lines. */
+  /** Every per-member background write this app makes to Emby under
+   *  someone's own account - the party watch-state sync (index.ts's
+   *  periodic sweep, and PartyService.advanceQueue/MusicQueueService
+   *  .playNext's own item-transition calls - see PlaystateService), and
+   *  the parallel Sessions-API lifecycle reported alongside it (see
+   *  EmbySessionService). Logs every outgoing request (method + path,
+   *  and the POST body for the UserData write) and its outcome, not
+   *  just failures: this is a best-effort background sync with nothing
+   *  else watching it, so `docker logs | grep watchparty:playstate`
+   *  needs to be enough on its own to see exactly what was sent and
+   *  whether Emby accepted it, without cross-referencing `emby` above.
+   *  Safe to log in full here (unlike `stream` above) - the real
+   *  embyToken travels as a header, never logged, and both services'
+   *  own tests confirm it never leaks into these lines. */
   static playstate(message: string): void {
     console.log(`[watchparty:playstate] ${new Date().toISOString()} ${message}`);
   }
+
+  /** Static (persistent) watch parties - created/joined/left/deleted,
+   *  group and per-member progress, sessions launched, and every load/save
+   *  of their JSON file (see StaticPartyService/StaticPartyStore). */
+  static staticParty(message: string): void {
+    console.log(`[watchparty:static] ${new Date().toISOString()} ${message}`);
+  }
 }

server/src/config.ts

@@ -17,3 +17,11 @@ if (!EMBY_SERVER_URL) {
 }
 
 export const PORT = Number(process.env.PORT) || 3000;
+
+/**
+ * Where persistent state lives on disk - today only the static watch
+ * parties (see StaticPartyStore). Relative paths resolve against the
+ * process's working directory. Mount a volume here in Docker, or every
+ * static watch party is lost with the container.
+ */
+export const DATA_DIR = process.env.DATA_DIR || './data';

server/src/index.ts

@@ -5,18 +5,24 @@ import http from 'http';
 import express, { type NextFunction, type Request, type Response } from 'express';
 import { Server as SocketIoServer } from 'socket.io';
 
-import { EMBY_SERVER_URL, PORT } from './config';
+import { DATA_DIR, EMBY_SERVER_URL, PORT } from './config';
 import { Logger } from './Logger';
 import { AuthService, SESSION_COOKIE, SESSION_TTL_MS } from './services/AuthService';
-import { CatalogService, CatalogFetchError, imageUrlFor, splitPlaylistByMediaType } from './services/CatalogService';
+import { CatalogService, CatalogFetchError, imageUrlFor, seasonQueue, seriesQueueFrom, splitPlaylistByMediaType } from './services/CatalogService';
 import { PartyService } from './services/PartyService';
 import { MusicQueueService } from './services/MusicQueueService';
 import { TranscodeService } from './services/TranscodeService';
 import { PartyStreamService } from './services/PartyStreamService';
 import { PlaystateService } from './services/PlaystateService';
+import { EmbySessionService } from './services/EmbySessionService';
 import { CastTokenService } from './services/CastTokenService';
+import { StaticPartyService } from './services/StaticPartyService';
+import { StaticPartyStore } from './services/StaticPartyStore';
 import { SocketGateway } from './realtime/SocketGateway';
-import type { ClientToServerEvents, EmbySession, MediaType, QueueItem, ServerToClientEvents } from './types';
+import type { ClientToServerEvents, EmbyItem, EmbySession, ItemDto, MediaType, MusicTrackInput, QueueItem, ServerToClientEvents, StaticParty } from './types';
+
+StaticPartyStore.configure(DATA_DIR);
+StaticPartyService.init();
 
 const app = express();
 app.set('trust proxy', 1); // behind openresty/nginx - needed for req.secure to reflect the real scheme
@@ -212,6 +218,13 @@ app.get('/api/catalog/item/:itemId/playback-options', requireSession, asyncRoute
   res.json(await CatalogService.getPlaybackOptions(req.embySession!, param(req, 'itemId')));
 }));
 
+// Emby's own native intro/credits detection, when the library it's from has
+// the feature enabled - powers the player's "Passer l'intro"/"Épisode
+// suivant" buttons. See CatalogService.getPlaybackMarkers.
+app.get('/api/catalog/item/:itemId/markers', requireSession, asyncRoute(async (req, res) => {
+  res.json(await CatalogService.getPlaybackMarkers(req.embySession!, param(req, 'itemId')));
+}));
+
 app.get('/api/catalog/libraries/:libraryId/items', requireSession, asyncRoute(async (req, res) => {
   res.json({ items: await CatalogService.getLibraryItems(req.embySession!, param(req, 'libraryId')) });
 }));
@@ -245,7 +258,7 @@ app.get('/api/catalog/party-stream/:partyId/master.m3u8', allowCastCors, asyncRo
   if (!session) { res.status(401).end(); return; }
   const party = PartyService.getById(partyId);
   if (!party || !party.members.has(session.userId)) {
-    res.status(403).json({ error: "Tu n'es pas membre de cette watch party." });
+    res.status(403).json({ error: "Tu n'es pas membre de cette party." });
     return;
   }
   await PartyStreamService.serveMasterPlaylist(req, res, party, session);
@@ -259,7 +272,7 @@ app.get('/api/catalog/party-stream/:partyId/raw', allowCastCors, asyncRoute(asyn
   if (!session) { res.status(401).end(); return; }
   const party = PartyService.getById(partyId);
   if (!party || !party.members.has(session.userId)) {
-    res.status(403).json({ error: "Tu n'es pas membre de cette watch party." });
+    res.status(403).json({ error: "Tu n'es pas membre de cette party." });
     return;
   }
   await PartyStreamService.serveRawAsset(req, res, party, session);
@@ -289,7 +302,7 @@ app.get('/api/catalog/burn/:partyId/master.m3u8', allowCastCors, asyncRoute(asyn
   if (!session) { res.status(401).end(); return; }
   const party = PartyService.getById(partyId);
   if (!party || !party.members.has(session.userId)) {
-    res.status(403).json({ error: "Tu n'es pas membre de cette watch party." });
+    res.status(403).json({ error: "Tu n'es pas membre de cette party." });
     return;
   }
   if (!party.burnInSubtitleIndex) {
@@ -305,7 +318,7 @@ app.get('/api/catalog/burn/:partyId/:segment', allowCastCors, asyncRoute(async (
   if (!session) { res.status(401).end(); return; }
   const party = PartyService.getById(partyId);
   if (!party || !party.members.has(session.userId)) {
-    res.status(403).json({ error: "Tu n'es pas membre de cette watch party." });
+    res.status(403).json({ error: "Tu n'es pas membre de cette party." });
     return;
   }
   await TranscodeService.serveSegment(req, res, party, param(req, 'segment'));
@@ -337,6 +350,32 @@ app.post('/api/parties', requireSession, asyncRoute(async (req, res) => {
     return;
   }
 
+  // Neither is itself streamable (same reason a Playlist above isn't) -
+  // launching one queues every track inside it instead: every album for
+  // an artist, every track for an album, in Emby's own sort order (see
+  // resolveMusicTracksForItem). Asked for directly, alongside the same
+  // action on the party's own existing queue - see the "queue" route
+  // below - both share this resolution.
+  // A whole series - every season, in order, from S1E1 (see
+  // seriesQueueFrom). Launched from the series page's own button or its
+  // library tile; an episode's own button still starts from that episode
+  // (the Episode branch below).
+  if (item.Type === 'Series') {
+    await createPartyFromSeries(res, session, item);
+    return;
+  }
+  // Just one season - the series page's per-season button (see seasonQueue).
+  if (item.Type === 'Season') {
+    await createPartyFromSeason(res, session, item);
+    return;
+  }
+
+  if (item.Type === 'MusicAlbum' || item.Type === 'MusicArtist') {
+    const tracks = await resolveMusicTracksForItem(session, item);
+    createMusicPartyFromTracks(res, session, tracks);
+    return;
+  }
+
   const mediaType: MediaType = item.Type === 'Audio' ? 'music' : 'video';
 
   // Starting a party from an episode queues the rest of the series from
@@ -347,13 +386,8 @@ app.post('/api/parties', requireSession, asyncRoute(async (req, res) => {
   let queue: QueueItem[] | null = null;
   if (mediaType === 'video' && item.Type === 'Episode' && item.SeriesId) {
     const all = await CatalogService.getAllSeriesEpisodesRaw(session, item.SeriesId);
-    const startIndex = all.findIndex((e) => e.Id === itemId);
-    const remaining = startIndex >= 0 ? all.slice(startIndex) : [item];
-    queue = remaining.map((e) => ({
-      itemId: e.Id,
-      itemName: formatEpisodeName(e),
-      itemImageUrl: `/api/catalog/image/${e.Id}`
-    }));
+    const remaining = seriesQueueFrom(all, itemId);
+    queue = (remaining.length ? remaining : [item]).map(toVideoQueueItem);
   }
 
   const party = PartyService.create(
@@ -390,6 +424,17 @@ function formatEpisodeName(episode: { ParentIndexNumber?: number; IndexNumber?:
   return episode.Name;
 }
 
+/** One video item (episode or movie) as a queue entry - shared by every
+ *  path that builds a video queue: an episode's series, a playlist, a
+ *  static watch party. */
+function toVideoQueueItem(item: EmbyItem): QueueItem {
+  return {
+    itemId: item.Id,
+    itemName: item.Type === 'Episode' ? formatEpisodeName(item) : item.Name,
+    itemImageUrl: `/api/catalog/image/${item.Id}`
+  };
+}
+
 /**
  * The "launch this playlist" half of POST /api/parties above - kept
  * separate rather than merged into the single-item path, which is
@@ -424,41 +469,19 @@ async function createPartyFromPlaylist(res: Response, session: EmbySession, play
   const items = startIndex > 0 ? allItems.slice(startIndex) : allItems;
 
   if (mediaType === 'music') {
-    const first = items[0]!;
-    const party = PartyService.create(
-      session.userId, session.userName,
-      first.Id, first.Name, imageUrlFor(first),
-      null, mediaType
-    );
-    PartyService.setMemberEmbyToken(party, session.userId, session.embyToken);
-    // Same mechanism POST /api/parties/:id/tracks already uses (see
-    // below) - init seeds+auto-starts the first track, addTrack queues
-    // the rest, exactly as if they'd been added one at a time.
-    items.forEach((track, i) => {
-      const trackInput = {
+    const trackInputs: MusicTrackInput[] = items.map((track) => ({
       itemId: track.Id,
       itemName: track.Name,
       artistName: track.AlbumArtist || track.Artists?.[0] || null,
       albumName: track.Album || null,
       itemImageUrl: imageUrlFor(track),
       durationTicks: track.RunTimeTicks || null
-      };
-      if (i === 0) {
-        MusicQueueService.init(party, trackInput, session.userId, session.userName);
-      } else {
-        MusicQueueService.addTrack(party, trackInput, session.userId, session.userName);
-      }
-    });
-    SocketGateway.broadcastLobby(io);
-    res.json(PartyService.toPublicState(party, session.userId));
+    }));
+    createMusicPartyFromTracks(res, session, trackInputs);
     return;
   }
 
-  const queue: QueueItem[] = items.map((e) => ({
-    itemId: e.Id,
-    itemName: e.Type === 'Episode' ? formatEpisodeName(e) : e.Name,
-    itemImageUrl: `/api/catalog/image/${e.Id}`
-  }));
+  const queue: QueueItem[] = items.map(toVideoQueueItem);
   const party = PartyService.create(
     session.userId, session.userName,
     queue[0]!.itemId, queue[0]!.itemName, queue[0]!.itemImageUrl,
@@ -469,6 +492,112 @@ async function createPartyFromPlaylist(res: Response, session: EmbySession, play
   res.json(PartyService.toPublicState(party, session.userId));
 }
 
+/** The "launch the whole series" half of POST /api/parties - a watch
+ *  party queued with every episode of every season (see seriesQueueFrom). */
+async function createPartyFromSeries(res: Response, session: EmbySession, series: EmbyItem): Promise<void> {
+  const episodes = await CatalogService.getAllSeriesEpisodesRaw(session, series.Id);
+  const queue = seriesQueueFrom(episodes).map(toVideoQueueItem);
+  if (!queue.length) {
+    res.status(400).json({ error: "Cette série n'a aucun épisode." });
+    return;
+  }
+  createVideoPartyFromQueue(res, session, queue, `series="${series.Name}"`);
+}
+
+/** The "launch just this season" half of POST /api/parties - only that
+ *  season's episodes, nothing after it (see seasonQueue). */
+async function createPartyFromSeason(res: Response, session: EmbySession, season: EmbyItem): Promise<void> {
+  if (!season.SeriesId) {
+    res.status(400).json({ error: 'Saison introuvable.' });
+    return;
+  }
+  const episodes = await CatalogService.getAllSeriesEpisodesRaw(session, season.SeriesId);
+  const queue = seasonQueue(episodes, season).map(toVideoQueueItem);
+  if (!queue.length) {
+    res.status(400).json({ error: "Cette saison n'a aucun épisode." });
+    return;
+  }
+  createVideoPartyFromQueue(res, session, queue, `season="${season.Name}" series=${season.SeriesId}`);
+}
+
+/** Creates a video watch party playing `queue` in order, hosted by
+ *  `session` - shared by the whole-series and single-season launches. */
+function createVideoPartyFromQueue(res: Response, session: EmbySession, queue: QueueItem[], logContext: string): void {
+  const first = queue[0]!;
+  const party = PartyService.create(session.userId, session.userName, first.itemId, first.itemName, first.itemImageUrl, queue, 'video');
+  PartyService.setMemberEmbyToken(party, session.userId, session.embyToken);
+  Logger.party(`queue launch partyId=${party.id} ${logContext} episodes=${queue.length}`);
+  SocketGateway.broadcastLobby(io);
+  res.json(PartyService.toPublicState(party, session.userId));
+}
+
+/** A raw Emby item known/expected to be music-shaped (Audio, MusicAlbum,
+ *  or MusicArtist - the three POST /api/parties and the "queue" route
+ *  below ever call this for) resolved into a flat, ordered track list -
+ *  a single track for Audio, every track in Emby's own IndexNumber order
+ *  for an album, every album's tracks in Emby's own ProductionYear/
+ *  SortName order for an artist's whole discography. Two Emby round
+ *  trips for an artist's own albums+tracks would be one call each if
+ *  this app ever needed to page through a huge discography - not
+ *  attempted speculatively, since Emby has yet to show any sign of
+ *  needing it for a personal library's worth of artists. */
+async function resolveMusicTracksForItem(session: EmbySession, item: EmbyItem): Promise<MusicTrackInput[]> {
+  if (item.Type === 'MusicAlbum') {
+    const tracks = await CatalogService.getAlbumTracks(session, item.Id);
+    return tracks.map(itemDtoToTrackInput);
+  }
+  if (item.Type === 'MusicArtist') {
+    const albums = await CatalogService.getArtistAlbums(session, item.Id);
+    const perAlbum = await Promise.all(albums.map((album) => CatalogService.getAlbumTracks(session, album.id)));
+    return perAlbum.flat().map(itemDtoToTrackInput);
+  }
+  // A single Audio track - the only other type this is ever called for.
+  return [{
+    itemId: item.Id,
+    itemName: item.Name,
+    artistName: item.AlbumArtist || item.Artists?.[0] || null,
+    albumName: item.Album || null,
+    itemImageUrl: imageUrlFor(item),
+    durationTicks: item.RunTimeTicks || null
+  }];
+}
+
+function itemDtoToTrackInput(item: ItemDto): MusicTrackInput {
+  return {
+    itemId: item.id,
+    itemName: item.name,
+    artistName: item.artistName,
+    albumName: item.albumName,
+    itemImageUrl: item.imageUrl,
+    durationTicks: item.durationTicks
+  };
+}
+
+/** Shared by every "launch this as a listen party" path that can produce
+ *  more than one track up front (an album, an artist's discography, a
+ *  music playlist - see createPartyFromPlaylist above and the
+ *  MusicAlbum/MusicArtist branch of POST /api/parties below) - seeds
+ *  party.music with `tracks`, in order: the first auto-starts,
+ *  everything else queues behind it via MusicQueueService.addTracks
+ *  (one broadcast for however many tracks that is, not one per track). */
+function createMusicPartyFromTracks(res: Response, session: EmbySession, tracks: MusicTrackInput[]): void {
+  if (!tracks.length) {
+    res.status(400).json({ error: 'Aucun morceau à lire.' });
+    return;
+  }
+  const [first, ...rest] = tracks;
+  const party = PartyService.create(
+    session.userId, session.userName,
+    first!.itemId, first!.itemName, first!.itemImageUrl,
+    null, 'music'
+  );
+  PartyService.setMemberEmbyToken(party, session.userId, session.embyToken);
+  MusicQueueService.init(party, first!, session.userId, session.userName);
+  MusicQueueService.addTracks(party, rest, session.userId, session.userName);
+  SocketGateway.broadcastLobby(io);
+  res.json(PartyService.toPublicState(party, session.userId));
+}
+
 // Adding a track to a music party's shared queue is REST, not a socket
 // event (see SocketGateway's top comment): the album-browsing page that
 // this is actually called from has no live connection to the party it's
@@ -479,12 +608,12 @@ async function createPartyFromPlaylist(res: Response, session: EmbySession, play
 app.post('/api/parties/:partyId/tracks', requireSession, (req, res) => {
   const party = PartyService.getById(param(req, 'partyId'));
   if (!party || party.mediaType !== 'music') {
-    res.status(404).json({ error: 'Watch party musique introuvable.' });
+    res.status(404).json({ error: 'Listen party introuvable.' });
     return;
   }
   const session = req.embySession!;
   if (!party.members.has(session.userId)) {
-    res.status(403).json({ error: "Tu n'es pas membre de cette watch party." });
+    res.status(403).json({ error: "Tu n'es pas membre de cette party." });
     return;
   }
   const track = req.body || {};
@@ -497,6 +626,39 @@ app.post('/api/parties/:partyId/tracks', requireSession, (req, res) => {
   res.json(PartyService.toPublicState(party, session.userId));
 });
 
+// Same "queue this item" resolution as the MusicAlbum/MusicArtist branch
+// of POST /api/parties above (a track queues itself; an album/artist
+// expands into every track inside it - see resolveMusicTracksForItem),
+// but adding into an ALREADY-LIVE party's queue instead of creating a
+// new one - views/album's and views/artist's own "add to queue" buttons.
+// Kept as its own route rather than overloading POST .../tracks above:
+// that one takes an already-built track object the caller already has
+// in hand (views/album's per-track buttons) - making it also guess
+// whether it received that or a bare id-to-resolve would be more
+// surprising than a second, clearly-named route.
+app.post('/api/parties/:partyId/queue', requireSession, asyncRoute(async (req, res) => {
+  const party = PartyService.getById(param(req, 'partyId'));
+  if (!party || party.mediaType !== 'music') {
+    res.status(404).json({ error: 'Listen party introuvable.' });
+    return;
+  }
+  const session = req.embySession!;
+  if (!party.members.has(session.userId)) {
+    res.status(403).json({ error: "Tu n'es pas membre de cette party." });
+    return;
+  }
+  const itemId = req.body?.itemId;
+  if (!itemId) {
+    res.status(400).json({ error: 'itemId is required.' });
+    return;
+  }
+  const item = await CatalogService.getRawItem(session, itemId);
+  const tracks = await resolveMusicTracksForItem(session, item);
+  MusicQueueService.addTracks(party, tracks, session.userId, session.userName);
+  SocketGateway.broadcastLobby(io); // the queue/now-playing preview may have just changed
+  res.json(PartyService.toPublicState(party, session.userId));
+}));
+
 app.post('/api/parties/:partyId/join', requireSession, (req, res) => {
   const party = PartyService.getById(param(req, 'partyId'));
   if (!party) {
@@ -506,6 +668,12 @@ app.post('/api/parties/:partyId/join', requireSession, (req, res) => {
   const session = req.embySession!;
   PartyService.join(party, session.userId, session.userName);
   PartyService.setMemberEmbyToken(party, session.userId, session.embyToken);
+  // Joining a static watch party's group session from the lobby makes you
+  // a member of that static party too - its progress is now yours.
+  if (party.staticLink?.mode === 'group') {
+    const sp = StaticPartyService.getById(party.staticLink.staticPartyId);
+    if (sp) StaticPartyService.join(sp, { userId: session.userId, userName: session.userName });
+  }
   SocketGateway.broadcastLobby(io); // member count changed - reflect it on the home page immediately
   res.json(PartyService.toPublicState(party, session.userId));
 });
@@ -513,10 +681,17 @@ app.post('/api/parties/:partyId/join', requireSession, (req, res) => {
 app.post('/api/parties/:partyId/leave', requireSession, (req, res) => {
   const party = PartyService.getById(param(req, 'partyId'));
   if (party) {
+    const member = party.members.get(req.embySession!.userId);
+    const deviceId = typeof req.body?.deviceId === 'string' ? req.body.deviceId : null;
+    // See PartyService.isStaleDevice's own comment for why this check
+    // exists at all - a REST call has no live connection to guard this
+    // with, unlike the socket "leave"/"disconnect" handlers.
+    if (!PartyService.isStaleDevice(member, deviceId)) {
       // Shared with the socket "leave"/"disconnect" handlers so the host-
       // handoff notification and the lobby refresh only live in one place.
       SocketGateway.applyLeave(io, party, req.embySession!.userId);
     }
+  }
   res.json({ ok: true });
 });
 
@@ -539,7 +714,7 @@ app.post('/api/parties/:partyId/cast-token', requireSession, (req, res) => {
   const party = PartyService.getById(param(req, 'partyId'));
   const session = req.embySession!;
   if (!party || !party.members.has(session.userId)) {
-    res.status(403).json({ error: "Tu n'es pas membre de cette watch party." });
+    res.status(403).json({ error: "Tu n'es pas membre de cette party." });
     return;
   }
   res.json({ token: CastTokenService.issue(party.id, session) });
@@ -553,6 +728,229 @@ app.delete('/api/parties/:partyId/cast-token', requireSession, (req, res) => {
   res.json({ ok: true });
 });
 
+// --- Static (persistent) watch parties ------------------------------------
+// A whole series/video playlist watched by a group over several sessions,
+// remembering the group's progress and each member's - see
+// StaticPartyService and spec/static-watch-party.md. Each session is an
+// ordinary live party (PartyService) linked back through party.staticLink.
+
+/** Fetches a static party's source under `session`'s own account - so
+ *  each item carries *their* Emby UserData (Played): the whole series
+ *  from S1E1 (specials left out - see seriesQueueFrom), one season's
+ *  episodes, or a playlist's video items. */
+async function fetchStaticSourceItems(session: EmbySession, source: StaticParty['source']): Promise<EmbyItem[]> {
+  if (source.type === 'series') {
+    return seriesQueueFrom(await CatalogService.getAllSeriesEpisodesRaw(session, source.sourceId));
+  }
+  if (source.type === 'season') {
+    if (!source.seriesId) return [];
+    const episodes = await CatalogService.getAllSeriesEpisodesRaw(session, source.seriesId);
+    return seasonQueue(episodes, { Id: source.sourceId, IndexNumber: source.seasonNumber });
+  }
+  const { mediaType, items } = splitPlaylistByMediaType(await CatalogService.getPlaylistItemsRaw(session, source.sourceId));
+  return mediaType === 'video' ? items : [];
+}
+
+/**
+ * Re-fetches `sp`'s source for `session`: merges any new item into it
+ * (StaticPartyService.refreshItems) and returns the ids Emby already has
+ * as Played for this user. Best-effort - Emby being unreachable must not
+ * make the page unusable, so a failure is logged and treated as "no
+ * Played info, no new items" (the in-app progress still works on its own).
+ */
+async function syncStaticSource(session: EmbySession, sp: StaticParty): Promise<Set<string>> {
+  try {
+    const raw = await fetchStaticSourceItems(session, sp.source);
+    StaticPartyService.refreshItems(sp, raw.map(toVideoQueueItem));
+    return new Set(raw.filter((i) => i.UserData?.Played).map((i) => i.Id));
+  } catch (err) {
+    Logger.staticParty(`source sync failed id=${sp.id} user=${Logger.who(session.userId, session.userName)}: ${(err as Error).message}`);
+    return new Set();
+  }
+}
+
+/** `sp`'s live group session id, if that party is still running - clears a
+ *  stale one (a party can end without its static party having heard). */
+function liveGroupPartyId(sp: StaticParty): string | null {
+  if (sp.livePartyId && !PartyService.getById(sp.livePartyId)) StaticPartyService.setLiveParty(sp, null);
+  return sp.livePartyId;
+}
+
+/** Finds `:staticId` or answers 404 - null means the response is sent. */
+function staticPartyOr404(req: Request, res: Response): StaticParty | null {
+  const sp = StaticPartyService.getById(param(req, 'staticId'));
+  if (!sp) res.status(404).json({ error: 'Lounge party introuvable.' });
+  return sp;
+}
+
+app.get('/api/static-parties', requireSession, asyncRoute(async (req, res) => {
+  const session = req.embySession!;
+  const parties = StaticPartyService.list();
+  const played = await Promise.all(parties.map((sp) => syncStaticSource(session, sp)));
+  res.json({
+    staticParties: parties.map((sp, i) => StaticPartyService.toSummary(sp, session.userId, played[i]!, liveGroupPartyId(sp)))
+  });
+}));
+
+app.post('/api/static-parties', requireSession, asyncRoute(async (req, res) => {
+  const sourceId = req.body?.sourceId;
+  if (!sourceId || typeof sourceId !== 'string') {
+    res.status(400).json({ error: 'sourceId is required.' });
+    return;
+  }
+  const session = req.embySession!;
+  const item = await CatalogService.getRawItem(session, sourceId);
+
+  // A whole series, one season of it, or a video playlist. An episode
+  // stands for its whole series - the natural entry point from
+  // views/series is the series itself, but nothing's lost accepting one.
+  // `sourceItem` is what gives the default name and the artwork: the
+  // series itself for a season (a season's own poster is often missing).
+  let source: StaticParty['source'];
+  let sourceItem = item;
+  let defaultName = item.Name;
+  if (item.Type === 'Series') {
+    source = { type: 'series', sourceId: item.Id };
+  } else if (item.Type === 'Season' && item.SeriesId) {
+    source = { type: 'season', sourceId: item.Id, seriesId: item.SeriesId, seasonNumber: item.IndexNumber };
+    sourceItem = await CatalogService.getRawItem(session, item.SeriesId);
+    defaultName = `${sourceItem.Name} - ${item.Name}`;
+  } else if (item.Type === 'Episode' && item.SeriesId) {
+    source = { type: 'series', sourceId: item.SeriesId };
+    sourceItem = await CatalogService.getRawItem(session, item.SeriesId);
+    defaultName = sourceItem.Name;
+  } else if (item.Type === 'Playlist') {
+    source = { type: 'playlist', sourceId: item.Id };
+  } else {
+    res.status(400).json({ error: 'Une lounge party se crée depuis une série, une saison ou une playlist vidéo.' });
+    return;
+  }
+
+  const raw = await fetchStaticSourceItems(session, source);
+  if (!raw.length) {
+    const emptyMessages = { series: "Cette série n'a aucun épisode.", season: "Cette saison n'a aucun épisode.", playlist: 'Cette playlist ne contient aucune vidéo.' };
+    res.status(400).json({ error: emptyMessages[source.type] });
+    return;
+  }
+  const name = typeof req.body?.name === 'string' && req.body.name.trim() ? req.body.name.trim() : defaultName;
+  const sp = StaticPartyService.create(
+    { userId: session.userId, userName: session.userName },
+    source, name, imageUrlFor(sourceItem), raw.map(toVideoQueueItem)
+  );
+  const played = new Set(raw.filter((i) => i.UserData?.Played).map((i) => i.Id));
+  res.json(StaticPartyService.toDetail(sp, session.userId, played, null));
+}));
+
+app.get('/api/static-parties/:staticId', requireSession, asyncRoute(async (req, res) => {
+  const sp = staticPartyOr404(req, res);
+  if (!sp) return;
+  const session = req.embySession!;
+  const played = await syncStaticSource(session, sp);
+  res.json(StaticPartyService.toDetail(sp, session.userId, played, liveGroupPartyId(sp)));
+}));
+
+app.post('/api/static-parties/:staticId/join', requireSession, (req, res) => {
+  const sp = staticPartyOr404(req, res);
+  if (!sp) return;
+  const session = req.embySession!;
+  StaticPartyService.join(sp, { userId: session.userId, userName: session.userName });
+  res.json({ ok: true });
+});
+
+app.post('/api/static-parties/:staticId/leave', requireSession, (req, res) => {
+  const sp = staticPartyOr404(req, res);
+  if (!sp) return;
+  StaticPartyService.leave(sp, req.embySession!.userId);
+  res.json({ ok: true });
+});
+
+app.delete('/api/static-parties/:staticId', requireSession, (req, res) => {
+  const sp = staticPartyOr404(req, res);
+  if (!sp) return;
+  if (!StaticPartyService.delete(sp, req.embySession!.userId)) {
+    res.status(403).json({ error: 'Seule la personne qui a créé cette lounge party peut la supprimer.' });
+    return;
+  }
+  res.json({ ok: true });
+});
+
+app.post('/api/static-parties/:staticId/items/:itemId/watched', requireSession, (req, res) => {
+  const sp = staticPartyOr404(req, res);
+  if (!sp) return;
+  const session = req.embySession!;
+  if (!StaticPartyService.markWatched(sp, { userId: session.userId, userName: session.userName }, param(req, 'itemId'))) {
+    res.status(404).json({ error: 'Cet élément ne fait pas partie de cette lounge party.' });
+    return;
+  }
+  res.json({ ok: true });
+});
+
+// Launches the group's next session - or joins it, if one's already
+// running. Whoever launches it hosts it (see PartyService.create), and it
+// resumes exactly where the group stopped last time: the host's starting
+// position is seeded from the saved one, which is what Player.ts already
+// reads to place every member's first frame (see its init()).
+app.post('/api/static-parties/:staticId/session', requireSession, asyncRoute(async (req, res) => {
+  const sp = staticPartyOr404(req, res);
+  if (!sp) return;
+  const session = req.embySession!;
+  const who = { userId: session.userId, userName: session.userName };
+
+  const existingId = liveGroupPartyId(sp);
+  if (!existingId) await syncStaticSource(session, sp); // pick up new episodes before building the queue
+  // Checked again after the await: someone else may have launched it meanwhile.
+  const liveId = liveGroupPartyId(sp);
+  const live = liveId ? PartyService.getById(liveId) : null;
+  if (live) {
+    PartyService.join(live, session.userId, session.userName);
+    PartyService.setMemberEmbyToken(live, session.userId, session.embyToken);
+    StaticPartyService.join(sp, who);
+    SocketGateway.broadcastLobby(io);
+    res.json({ partyId: live.id });
+    return;
+  }
+
+  const queue = StaticPartyService.groupQueue(sp);
+  if (!queue.length) {
+    res.status(409).json({ error: 'Le groupe a déjà tout vu dans cette lounge party.' });
+    return;
+  }
+  const first = queue[0]!;
+  const party = PartyService.create(session.userId, session.userName, first.itemId, first.itemName, first.itemImageUrl, queue, 'video');
+  party.staticLink = { staticPartyId: sp.id, mode: 'group' };
+  party.members.get(session.userId)!.positionTicks = sp.group.resumePositionTicks;
+  PartyService.setMemberEmbyToken(party, session.userId, session.embyToken);
+  StaticPartyService.join(sp, who);
+  StaticPartyService.setLiveParty(sp, party.id);
+  SocketGateway.broadcastLobby(io);
+  res.json({ partyId: party.id });
+}));
+
+// Catching up on missed items - alone (a party hidden from the lobby) or as
+// an ordinary watch party others can join. Only the participants' own
+// progress changes; the group's doesn't (see StaticPartyService.onItemCompleted).
+app.post('/api/static-parties/:staticId/catch-up', requireSession, (req, res) => {
+  const sp = staticPartyOr404(req, res);
+  if (!sp) return;
+  const session = req.embySession!;
+  const mode = req.body?.mode === 'party' ? 'party' : 'solo';
+  const requested = new Set(Array.isArray(req.body?.itemIds) ? req.body.itemIds.filter((id: unknown) => typeof id === 'string') : []);
+  const queue = sp.items.filter((i) => requested.has(i.itemId)); // the static party's own order, never the caller's
+  if (!queue.length) {
+    res.status(400).json({ error: 'Aucun élément à rattraper.' });
+    return;
+  }
+  const first = queue[0]!;
+  const party = PartyService.create(session.userId, session.userName, first.itemId, first.itemName, first.itemImageUrl, queue, 'video');
+  party.staticLink = { staticPartyId: sp.id, mode: 'catchUp' };
+  party.hiddenFromLobby = mode === 'solo';
+  PartyService.setMemberEmbyToken(party, session.userId, session.embyToken);
+  StaticPartyService.join(sp, { userId: session.userId, userName: session.userName });
+  Logger.staticParty(`catch-up started id=${sp.id} mode=${mode} partyId=${party.id} items=${queue.length} by=${Logger.who(session.userId, session.userName)}`);
+  if (!party.hiddenFromLobby) SocketGateway.broadcastLobby(io);
+  res.json({ partyId: party.id });
+});
+
 // Catches whatever asyncRoute() forwarded (or a synchronous throw) -
 // CatalogFetchError carries its own status/message; anything else is an
 // unexpected bug, logged in full server-side but never leaked to the
@@ -606,17 +1004,70 @@ setInterval(() => PartyStreamService.reapIdleSessions(30 * 60 * 1000), 5 * 60 *
 // Marking an item Played (once the party moves past it) is handled
 // separately, at the source of that transition - see
 // PartyService.advanceQueue and MusicQueueService.playNext.
+//
+// Also where EmbySessionService's own start/progress/stop lifecycle is
+// driven from, rather than scattered across every queue-advance/track-
+// skip call site the way markPlayed needed to be - this loop already
+// visits every connected member on every tick, so it's already in
+// exactly the right place to notice "this member's current item just
+// changed" (member.embySession.itemId no longer matches) and react:
+// stop the old session if there was one, negotiate a fresh
+// MediaSourceId/PlaySessionId under their own account, and start the
+// new one. Same item as last tick just reports Progress with the
+// already-cached ids - no renegotiation needed for that, the common case.
 setInterval(() => {
   for (const party of PartyService.listActive()) {
     const state = PartyService.getCurrentPlaybackState(party);
     if (!state) continue; // nothing currently playing (e.g. an empty music queue)
+    // A static watch party's group session: remember where the group is,
+    // so the next session resumes there (no-op for any other party).
+    if (party.staticLink) StaticPartyService.recordPosition(party.staticLink, state.itemId, state.positionTicks);
     for (const member of party.members.values()) {
       if (!member.connection || !member.embyToken) continue;
       PlaystateService.updatePosition(member.embyToken, member.userId, state.itemId, state.positionTicks);
+
+      if (member.embySession && member.embySession.itemId === state.itemId) {
+        const s = member.embySession;
+        EmbySessionService.progress(member.embyToken, s.itemId, s.mediaSourceId, s.playSessionId, state.positionTicks, state.isPaused);
+        continue;
+      }
+
+      // The item just changed for them (or this is the first tick since
+      // they started watching/listening) - stop whatever they had open
+      // before, if anything, then negotiate and start a fresh one.
+      const previous = member.embySession;
+      const embyToken = member.embyToken;
+      member.embySession = null;
+      if (previous) {
+        EmbySessionService.stop(embyToken, previous.itemId, previous.mediaSourceId, previous.playSessionId, member.positionTicks);
+      }
+      // CatalogService's own methods all take a full EmbySession, for
+      // consistency with every live user-facing route that already has
+      // one from requireSession - this sweep only ever has a member's
+      // bare stored token, same situation PlaystateService/
+      // EmbySessionService are already in. serverId/createdUtc are safe
+      // to fake: negotiatePlaybackSession (like every per-member Emby
+      // write in this app) never reads either, only embyToken/userId.
+      const fakeSession: EmbySession = { embyToken, userId: member.userId, userName: member.userName, serverId: '', createdUtc: 0 };
+      CatalogService.negotiatePlaybackSession(fakeSession, state.itemId).then((negotiated) => {
+        if (!negotiated) return;
+        member.embySession = { itemId: state.itemId, mediaSourceId: negotiated.mediaSourceId, playSessionId: negotiated.playSessionId };
+        EmbySessionService.start(embyToken, state.itemId, negotiated.mediaSourceId, negotiated.playSessionId, state.positionTicks, state.isPaused);
+      });
     }
   }
 }, 20 * 1000);
 
+// A pending (debounced) static-party save must reach disk before the
+// process exits - `docker stop` sends SIGTERM, Ctrl+C sends SIGINT.
+for (const signal of ['SIGTERM', 'SIGINT'] as const) {
+  process.once(signal, () => {
+    Logger.staticParty(`${signal} received - flushing before exit`);
+    StaticPartyStore.flushSync();
+    process.exit(0);
+  });
+}
+
 server.listen(PORT, () => {
   console.log(`[watchparty] listening on :${PORT} (Emby server: ${EMBY_SERVER_URL || 'NOT SET'})`);
 });

server/src/realtime/SocketGateway.ts

@@ -3,6 +3,7 @@
 import { Logger } from '../Logger';
 import { MusicQueueService } from '../services/MusicQueueService';
 import { PartyService } from '../services/PartyService';
+import { StaticPartyService } from '../services/StaticPartyService';
 import type { AppServer, LeaveResult, LobbyPartyDto, Party, SocketMemberDto } from '../types';
 
 /**
@@ -35,6 +36,9 @@ import type { AppServer, LeaveResult, LobbyPartyDto, Party, SocketMemberDto } fr
  *   "playstate" {isPaused, positionTicks}   (host only - ignored otherwise)
  *   "playstate" (server -> client, to everyone in the party but the sender)
  *   "next"                                  (host only - advance the queue)
+ *   "itemEnded"                             (host only - the last queued item
+ *                                            played to its end; counts it as
+ *                                            completed without advancing)
  *   "itemChanged" (server -> client)
  *   "setBurnInSubtitle" {subtitleIndex, audioIndex?}  (host only - picks
  *     or clears the party's *shared* self-hosted-ffmpeg burn-in stream,
@@ -207,6 +211,17 @@ class SocketGatewayClass {
         }
       }));
 
+      // The last queued item played to its end - nothing to advance to,
+      // but it still counts as completed (Emby Played flag, static watch
+      // party progress). Host-only, same as "next".
+      socket.on('itemEnded', this.safe(() => {
+        if (!party || userId !== party.hostUserId) {
+          return;
+        }
+        Logger.party(`item ended partyId=${party.id} item="${party.itemName}" (${party.queueIndex + 1}/${party.queue.length})`);
+        PartyService.completeCurrentItem(party);
+      }));
+
       // Host-only, video-only: picks (or clears) the party's *shared*
       // burn-in stream - see TranscodeService and Party.burnInSubtitleIndex's
       // own comment. Deliberately doesn't touch TranscodeService directly
@@ -283,6 +298,12 @@ class SocketGatewayClass {
         MusicQueueService.setPaused(party, !!msg?.isPaused);
       }));
 
+      // No host check either, same reasoning - see MusicQueueService.seek.
+      socket.on('musicSeek', this.safe((msg: { positionSeconds: number }) => {
+        if (!party || party.mediaType !== 'music' || !party.members.get(userId)) return;
+        MusicQueueService.seek(party, Number(msg?.positionSeconds) || 0);
+      }));
+
       // Anyone (not just followers - harmless either way) can ask the host
       // to pause; the presence overlay (the video player) is what triggers
       // this. Broadcast to the whole party, not just the host, so everyone
@@ -404,8 +425,11 @@ class SocketGatewayClass {
   }
 
   private lobbySnapshot(): LobbyPartyDto[] {
-    return PartyService.listActive().map((party) => {
+    // A solo catch-up session of a static watch party isn't something
+    // anyone else should see or join - see Party.hiddenFromLobby.
+    return PartyService.listActive().filter((party) => !party.hiddenFromLobby).map((party) => {
       const host = party.members.get(party.hostUserId);
+      const staticParty = party.staticLink ? StaticPartyService.getById(party.staticLink.staticPartyId) : null;
       // Video only - see LobbyPartyDto's own comment for why music parties
       // get null here and fall back to createdUtc client-side instead.
       // The host is authoritative for position/pause the same way they are
@@ -423,7 +447,9 @@ class SocketGatewayClass {
         createdUtc: party.createdUtc, // client computes/ticks elapsed time itself from this
         positionTicks: isVideo && host ? host.positionTicks : null,
         isPaused: isVideo && host ? host.isPaused : null,
-        positionUpdatedUtc: isVideo && host ? host.lastUpdatedUtc : null
+        positionUpdatedUtc: isVideo && host ? host.lastUpdatedUtc : null,
+        staticPartyId: staticParty ? staticParty.id : null,
+        staticPartyName: staticParty ? staticParty.name : null
       };
     });
   }

server/src/services/CatalogService.ts

@@ -4,14 +4,15 @@ import type { Request, Response } from 'express';
 import { EMBY_SERVER_URL } from '../config';
 import { EmbyClient } from '../emby/EmbyClient';
 import { Logger } from '../Logger';
-import type { EmbyItem, EmbySession, ItemDto, LibraryDto, MediaType, PlaybackOptionsDto, SeasonDto } from '../types';
+import type { EmbyItem, EmbySession, ItemDto, LibraryDto, MediaType, PlaybackMarkersDto, PlaybackOptionsDto, SeasonDto } from '../types';
 
 // 'MusicVideo' is Emby's own item type for a musicvideos library's
 // contents (distinct from the generic 'Video', which is home videos).
-// 'Audio' is a music track. Series/Season/MusicArtist/MusicAlbum aren't
-// directly playable - only show "start a party" for things Emby can
-// actually stream. "Voir sur Emby" always works though.
-const WATCH_PARTY_TYPES = new Set(['Movie', 'Episode', 'Video', 'MusicVideo', 'Audio']);
+// 'Audio' is a music track. 'Series' isn't itself streamable, but
+// launching one queues the whole series (see seriesQueueFrom and POST
+// /api/parties). Season/MusicArtist/MusicAlbum get no tile button - their
+// own pages have their own launch actions. "Voir sur Emby" always works.
+const WATCH_PARTY_TYPES = new Set(['Movie', 'Episode', 'Video', 'MusicVideo', 'Audio', 'Series']);
 
 // Emby's /Views can return all sorts of things beyond actual media
 // libraries - boxset collections, live TV, photos, books, a mixed-content
@@ -68,6 +69,36 @@ export function imageUrlFor(item: EmbyItem): string {
   return `/api/catalog/image/${imageItemId}`;
 }
 
+/**
+ * What a watch party queues from a series' full episode list (Emby's own
+ * order, every season - see getAllSeriesEpisodesRaw): everything from
+ * `fromEpisodeId` on, or - when launching the whole series - everything
+ * from its first regular episode on. Specials (season 0) sort first in
+ * Emby's list, so "the whole series" deliberately starts at S1E1, the
+ * same queue clicking S1E1's own button builds. An unknown
+ * `fromEpisodeId` yields an empty list (the caller falls back to the one
+ * item). Pure.
+ */
+export function seriesQueueFrom(episodes: EmbyItem[], fromEpisodeId?: string): EmbyItem[] {
+  if (fromEpisodeId) {
+    const index = episodes.findIndex((e) => e.Id === fromEpisodeId);
+    return index >= 0 ? episodes.slice(index) : [];
+  }
+  const firstRegular = episodes.findIndex((e) => e.ParentIndexNumber !== 0);
+  return firstRegular >= 0 ? episodes.slice(firstRegular) : episodes;
+}
+
+/**
+ * Just one season's episodes, in Emby's order, out of a series' full
+ * episode list - "launch this season". Matched by SeasonId, falling back
+ * to the season number for an episode Emby returned without one. Pure.
+ */
+export function seasonQueue(episodes: EmbyItem[], season: { Id: string; IndexNumber?: number }): EmbyItem[] {
+  return episodes.filter((e) => e.SeasonId
+    ? e.SeasonId === season.Id
+    : season.IndexNumber != null && e.ParentIndexNumber === season.IndexNumber);
+}
+
 export function splitPlaylistByMediaType(items: EmbyItem[]): { mediaType: MediaType; items: EmbyItem[] } {
   if (!items.length) return { mediaType: 'video', items: [] };
   const isMusic = items[0]!.Type === 'Audio';
@@ -125,9 +156,23 @@ class CatalogServiceClass {
    *  mediaType from the clicked item's real Emby Type (see index.ts).
    *  Unlike every other method here, this preserves Emby's own status
    *  (typically a real 404) rather than a blanket 502 - "titre introuvable"
-   *  is a not-found, not an upstream failure. */
+   *  is a not-found, not an upstream failure.
+   *
+   *  `Fields=AlbumId` - without it, Emby's default field set for a single
+   *  item omits it, so a track started directly (not via its album/
+   *  artist - the one path that reaches imageUrlFor through *this*
+   *  method, in index.ts's POST /api/parties) always missed imageUrlFor's
+   *  own Audio -> AlbumId fallback and fell through to the track's own
+   *  id instead - which, confirmed directly against a real server (see
+   *  imageUrlFor's own comment), essentially never has a Primary image
+   *  of its own. Reported directly as "the app really struggles to find
+   *  artist/album/track images" - this is the one concrete, fixable
+   *  piece of that: a party started this way now gets the same album
+   *  art every other path already resolves correctly. Harmless for
+   *  every non-Audio item this also fetches (Movie/Series/Episode/...) -
+   *  they have no AlbumId to begin with, so Emby just omits the field. */
   async getRawItem(session: EmbySession, itemId: string): Promise<EmbyItem> {
-    return this.fetchJson<EmbyItem>(`/Users/${session.userId}/Items/${itemId}`, session, 'Titre introuvable.', { preserveEmbyStatus: true });
+    return this.fetchJson<EmbyItem>(`/Users/${session.userId}/Items/${itemId}?Fields=AlbumId`, session, 'Titre introuvable.', { preserveEmbyStatus: true });
   }
 
   async getItem(session: EmbySession, itemId: string): Promise<ItemDto> {
@@ -205,7 +250,7 @@ class CatalogServiceClass {
     // so a 300 cap would have silently dropped 75% of them, not just
     // trimmed an edge case. Rendering that many is tiles.ts's
     // renderTilesInChunks's job, not this query's.
-    const params = new URLSearchParams({ ParentId: libraryId, UserId: session.userId, SortBy: 'SortName' });
+    const params = new URLSearchParams({ ParentId: libraryId, UserId: session.userId, SortBy: 'SortName', Fields: 'SortName' });
     const data = await this.fetchJson<EmbyItemsResponse>(`/Artists?${params}`, session, 'Impossible de récupérer les artistes.');
     return (data.Items || []).map((a) => this.toItemDto(a, session.serverId));
   }
@@ -261,7 +306,7 @@ class CatalogServiceClass {
       ParentId: libraryId,
       Recursive: 'false', // top-level: Movies as movies, TV as Series tiles (not every episode)
       SortBy: 'SortName',
-      Fields: 'ProductionYear,AlbumId',
+      Fields: 'ProductionYear,AlbumId,SortName',
       ImageTypeLimit: '1'
     });
     const data = await this.fetchJson<EmbyItemsResponse>(`/Users/${session.userId}/Items?${params}`, session, 'Impossible de récupérer le contenu de cette bibliothèque.');
@@ -286,6 +331,30 @@ class CatalogServiceClass {
     };
   }
 
+  /**
+   * Emby's own native intro/credits detection - see PlaybackMarkersDto's
+   * own comment for what MarkerType actually looks like and where that
+   * was confirmed. Read from the same Chapters field getRawItem/toItemDto
+   * never request (they have no use for chapters at all) - a dedicated
+   * fetch here rather than folding it into getItem, since a chapter list
+   * is only ever needed by the player deciding whether to show a skip
+   * button, nowhere a plain ItemDto is used.
+   */
+  async getPlaybackMarkers(session: EmbySession, itemId: string): Promise<PlaybackMarkersDto> {
+    const data = await this.fetchJson<{ Chapters?: Array<{ StartPositionTicks: number; MarkerType?: string }> }>(
+      `/Users/${session.userId}/Items/${itemId}?Fields=Chapters`,
+      session,
+      'Impossible de récupérer les marqueurs de lecture.'
+    );
+    const chapters = data.Chapters || [];
+    const startOf = (markerType: string) => chapters.find((c) => c.MarkerType === markerType)?.StartPositionTicks ?? null;
+    return {
+      introStartTicks: startOf('IntroStart'),
+      introEndTicks: startOf('IntroEnd'),
+      creditsStartTicks: startOf('CreditsStart')
+    };
+  }
+
   /**
    * The negotiated MediaSource's id/container/streams - used by
    * TranscodeService to build its own ffmpeg source URL and translate
@@ -307,6 +376,33 @@ class CatalogServiceClass {
     return { id: source.Id, container: source.Container || 'mkv', streams: source.MediaStreams || [] };
   }
 
+  /**
+   * A fresh PlaybackInfo negotiation under `session`'s own account,
+   * purely to get the MediaSourceId/PlaySessionId EmbySessionService
+   * needs to open a real Emby Sessions-API entry for this member - see
+   * its own class comment for why every party member needs their own,
+   * rather than reusing the one PartyStreamService already negotiated
+   * for the party's actual shared relay (that one was negotiated once,
+   * under whichever member happened to trigger it first - never
+   * guaranteed valid for every OTHER member's own account, since Emby
+   * scopes PlaybackInfo per user). Null on any failure (an expired
+   * token, Emby unreachable, no source at all) rather than throwing -
+   * this is reported to an admin dashboard as a nice-to-have, never
+   * something that should be allowed to disrupt real playback the way
+   * getMediaSource's own hard failure is allowed to (that one feeds an
+   * actual ffmpeg source).
+   */
+  async negotiatePlaybackSession(session: EmbySession, itemId: string): Promise<{ mediaSourceId: string; playSessionId: string } | null> {
+    try {
+      const info = await this.fetchJson<PlaybackInfoResponse>(`/Items/${itemId}/PlaybackInfo?UserId=${session.userId}`, session, 'Impossible de négocier une session de lecture.');
+      const source = (info.MediaSources || [])[0];
+      if (!source?.Id || !info.PlaySessionId) return null;
+      return { mediaSourceId: source.Id, playSessionId: info.PlaySessionId };
+    } catch {
+      return null;
+    }
+  }
+
   // --- Direct proxying (images/video/audio) - these need the raw
   // Express req/res, unlike everything above which just returns JSON. ---
 
@@ -452,6 +548,7 @@ class CatalogServiceClass {
     return {
       id: item.Id,
       name: item.Name,
+      sortName: item.SortName || item.Name,
       overview: item.Overview,
       year: item.ProductionYear,
       type: item.Type,

server/src/services/EmbySessionService.ts

@@ -0,0 +1,104 @@
+'use strict';
+
+import { EmbyClient } from '../emby/EmbyClient';
+import { Logger } from '../Logger';
+
+/**
+ * Reports a party member's own playback to Emby's real Sessions API
+ * (`POST /Sessions/Playing`, `/Sessions/Playing/Progress`,
+ * `/Sessions/Playing/Stopped`) - the piece of session lifecycle
+ * docs/architecture.md's "Sync watch-party progress back to Emby"
+ * section deliberately deferred at the time ("wiring clean start/stop
+ * into every transition... is real complexity for a secondary payoff").
+ * Asked for directly since: without this, this app's own streams never
+ * showed up in Emby's admin "now playing" dashboard the way a real web/
+ * mobile/TV client's would - only the resume-position/watched-history
+ * UserData (PlaystateService) was ever visible anywhere, and only by
+ * opening the item itself, not from the dashboard's live session list.
+ *
+ * One real Emby session per PARTY MEMBER, not one per party - a
+ * faithful copy of how a real client behaves (every device/account gets
+ * its own), and the actual point of the request ("let admin see who's
+ * watching what") would be lost by collapsing every member onto one
+ * shared entry. Every call needs the member's own `embyToken` (the same
+ * source every other per-member Emby write in this app already uses -
+ * see `PartyMember.embyToken`/`PlaystateService`) - Emby's Sessions API
+ * is inherently per-account, there's no equivalent of "the party's" own
+ * session to report against instead.
+ *
+ * `MediaSourceId`/`PlaySessionId` (see `CatalogService
+ * .negotiatePlaybackSession`) are required in practice, not just
+ * present in the schema - confirmed by reading the real server's own
+ * `/openapi.json` rather than assumed, after this exact neighboring
+ * area (`PlaystateService`'s own history) already got bitten twice by
+ * an Emby endpoint accepting a request shape that looked complete but
+ * wasn't. `index.ts`'s periodic sweep is what actually drives the
+ * start/progress/stop transitions - see its own comment for why that
+ * one place could cover this instead of scattering hooks across every
+ * queue-advance/track-skip call site the way `PlaystateService
+ * .markPlayed` needed to.
+ *
+ * Best-effort throughout, exactly like `PlaystateService`: any failure
+ * is caught and logged here, never thrown - none of this may ever
+ * disrupt real playback over an admin-dashboard nicety.
+ */
+class EmbySessionServiceClass {
+  /** Called once per member when they start watching/listening to
+   *  `itemId` - a fresh join, or the party moving to a new item while
+   *  they're already a member (see index.ts's sweep, which detects that
+   *  by comparing against `PartyMember.embySession.itemId`). */
+  async start(embyToken: string, itemId: string, mediaSourceId: string, playSessionId: string, positionTicks: number, isPaused: boolean): Promise<void> {
+    await this.report('/Sessions/Playing', embyToken, {
+      ItemId: itemId,
+      MediaSourceId: mediaSourceId,
+      PlaySessionId: playSessionId,
+      PositionTicks: Math.round(positionTicks),
+      IsPaused: isPaused,
+      PlayMethod: 'Transcode',
+      CanSeek: true
+    });
+  }
+
+  /** Called periodically (~20s, alongside `PlaystateService
+   *  .updatePosition` - see index.ts's sweep) for every member with a
+   *  live session already open for their current item. */
+  async progress(embyToken: string, itemId: string, mediaSourceId: string, playSessionId: string, positionTicks: number, isPaused: boolean): Promise<void> {
+    await this.report('/Sessions/Playing/Progress', embyToken, {
+      ItemId: itemId,
+      MediaSourceId: mediaSourceId,
+      PlaySessionId: playSessionId,
+      PositionTicks: Math.round(positionTicks),
+      IsPaused: isPaused,
+      PlayMethod: 'Transcode'
+    });
+  }
+
+  /** Called once per member when they stop watching/listening to
+   *  `itemId` - leaving the party (`PartyService.leave`), the item
+   *  changing (index.ts's sweep), or the party being destroyed for
+   *  inactivity (`PartyService.removeIdleParties`). */
+  async stop(embyToken: string, itemId: string, mediaSourceId: string, playSessionId: string, positionTicks: number): Promise<void> {
+    await this.report('/Sessions/Playing/Stopped', embyToken, {
+      ItemId: itemId,
+      MediaSourceId: mediaSourceId,
+      PlaySessionId: playSessionId,
+      PositionTicks: Math.round(positionTicks)
+    });
+  }
+
+  /** Every call logs its own outgoing request + outcome - see
+   *  Logger.playstate's own comment for why this needs to be enough on
+   *  its own, greppable, to answer "is this actually reaching Emby, and
+   *  with what" for this service too, not just PlaystateService. */
+  private async report(path: string, embyToken: string, body: Record<string, unknown>): Promise<void> {
+    Logger.playstate(`-> POST ${path} itemId=${body.ItemId}`);
+    try {
+      const res = await EmbyClient.fetch(path, embyToken, { method: 'POST', body });
+      Logger.playstate(`<- ${res.status} ${res.ok ? 'ok' : 'FAILED'} ${path} itemId=${body.ItemId}`);
+    } catch (err) {
+      Logger.playstate(`<- threw ${path} itemId=${body.ItemId}: ${(err as Error).message}`);
+    }
+  }
+}
+
+export const EmbySessionService = new EmbySessionServiceClass();

server/src/services/MusicQueueService.ts

@@ -52,7 +52,42 @@ class MusicQueueServiceClass {
 
   addTrack(party: Party, track: MusicTrackInput, addedByUserId: string, addedByUserName: string): void {
     const music = party.music!;
-    const entry: MusicTrack = {
+    const entry = this.buildTrackEntry(track, addedByUserId, addedByUserName);
+    music.queue.push(entry);
+    party.lastActivityUtc = Date.now();
+    Logger.party(`musicQueueAdd partyId=${party.id} user=${Logger.who(addedByUserId, addedByUserName)} track="${entry.itemName}" queueLength=${music.queue.length}`);
+    if (!music.current) {
+      this.playNext(party); // queue was empty - this track starts immediately
+    }
+    this.broadcast(party);
+  }
+
+  /**
+   * Same per-track behavior as addTrack (auto-starts if the queue was
+   * empty when the first of these lands), but ONE broadcast at the end
+   * instead of one per track - asked for directly, to queue a whole
+   * album or an artist's entire discography in one action rather than
+   * one track at a time. Without this, a hundred-track discography
+   * would spam the party with a hundred intermediate "queueUpdated"
+   * events for what's really a single user action - see index.ts's
+   * createMusicPartyFromTracks/the "queue" route, the two callers.
+   */
+  addTracks(party: Party, tracks: MusicTrackInput[], addedByUserId: string, addedByUserName: string): void {
+    if (!tracks.length) return;
+    const music = party.music!;
+    for (const track of tracks) {
+      music.queue.push(this.buildTrackEntry(track, addedByUserId, addedByUserName));
+      if (!music.current) {
+        this.playNext(party);
+      }
+    }
+    party.lastActivityUtc = Date.now();
+    Logger.party(`musicQueueAddBatch partyId=${party.id} user=${Logger.who(addedByUserId, addedByUserName)} count=${tracks.length} queueLength=${music.queue.length}`);
+    this.broadcast(party);
+  }
+
+  private buildTrackEntry(track: MusicTrackInput, addedByUserId: string, addedByUserName: string): MusicTrack {
+    return {
       itemId: track.itemId,
       itemName: track.itemName,
       artistName: track.artistName || null,
@@ -64,13 +99,6 @@ class MusicQueueServiceClass {
       addedByUserId,
       addedByUserName
     };
-    music.queue.push(entry);
-    party.lastActivityUtc = Date.now();
-    Logger.party(`musicQueueAdd partyId=${party.id} user=${Logger.who(addedByUserId, addedByUserName)} track="${entry.itemName}" queueLength=${music.queue.length}`);
-    if (!music.current) {
-      this.playNext(party); // queue was empty - this track starts immediately
-    }
-    this.broadcast(party);
   }
 
   /** No host check - anyone can toggle this (see class comment). */
@@ -92,6 +120,41 @@ class MusicQueueServiceClass {
     this.broadcast(party);
   }
 
+  /**
+   * No host check - anyone can do this (see class comment): a seek is
+   * just a continuous version of pause/resume, reversible and not a
+   * change to what's playing - not the majority-vote model reserved for
+   * actually skipping to different content. Clamped into
+   * [0, durationSeconds] when the duration is known (an unknown one -
+   * never actually seen in practice, see MusicTrack - just trusts the
+   * caller's own non-negative value, same as the video player's seek
+   * has no server-side duration to clamp against either).
+   */
+  seek(party: Party, positionSeconds: number): void {
+    const current = party.music?.current;
+    if (!current) return;
+    const duration = current.track.durationSeconds;
+    const clampedSeconds = Math.max(0, duration != null ? Math.min(positionSeconds, duration) : positionSeconds);
+    const elapsedMs = clampedSeconds * 1000;
+    if (current.isPaused) {
+      current.pausedElapsedMs = elapsedMs;
+    } else {
+      // Must clear the existing timer first, not just overwrite it -
+      // scheduleAdvance only ever sets advanceTimer, it never clears a
+      // prior one itself (setPaused's own resume branch gets away with
+      // skipping this only because pausing already cleared it - see its
+      // own "if (isPaused)" branch). Skipping this here would leave the
+      // OLD, now-wrong-duration timer running alongside the new one,
+      // eventually firing playNext at the wrong time.
+      this.clearTimer(party);
+      current.startedUtc = Date.now() - elapsedMs;
+      this.scheduleAdvance(party);
+    }
+    party.lastActivityUtc = Date.now();
+    Logger.party(`musicSeek partyId=${party.id} -> ${clampedSeconds}s`);
+    this.broadcast(party);
+  }
+
   /**
    * Registers `userId`'s vote to skip the current track - a strict
    * majority of `connectedMemberCount` (computed by the caller, which has

server/src/services/PartyService.ts

@@ -7,6 +7,8 @@ import { TranscodeService } from './TranscodeService';
 import { PartyStreamService } from './PartyStreamService';
 import { PlaystateService } from './PlaystateService';
 import { CastTokenService } from './CastTokenService';
+import { EmbySessionService } from './EmbySessionService';
+import { StaticPartyService } from './StaticPartyService';
 import type { LeaveResult, MediaType, Party, PartyMember, PartyPublicState, QueueItem } from '../types';
 
 /**
@@ -143,6 +145,30 @@ class PartyServiceClass {
     return { itemId: party.itemId, positionTicks: host.positionTicks, isPaused: host.isPaused };
   }
 
+  /**
+   * Whether a request claiming to be `deviceId` is stale for `member` -
+   * already replaced by a takeover on a *different* device (see
+   * SocketGateway's "join" handler). Used by the REST /leave route
+   * (index.ts), which - unlike the socket "leave"/"disconnect" handlers,
+   * guarded by comparing `member.connection` against the live socket
+   * itself - has no connection to compare against instead. Without this,
+   * a device already superseded by a takeover elsewhere could still call
+   * /leave and end the CURRENT device's membership by mistake - confirmed
+   * as the real cause of a "both devices end up on the session, controls
+   * never transfer" report: the stale device's own client didn't react to
+   * being disconnected at all (see Player.ts/MusicBar.ts's onClose), so
+   * its still-rendered "Quitter" button stayed clickable and reached here.
+   *
+   * Only ever returns true on positive evidence of a mismatch (both sides
+   * known and different) - a member with no recorded deviceId yet, or a
+   * caller that didn't send one, is never treated as stale, mirroring the
+   * socket handlers' own "nothing to conflict with yet" reasoning for a
+   * null deviceId.
+   */
+  isStaleDevice(member: PartyMember | undefined, deviceId: string | null): boolean {
+    return !!(member?.deviceId && deviceId && member.deviceId !== deviceId);
+  }
+
   /**
    * Removes a member. If they were the host, promotes whoever's left
    * (arbitrary but deterministic-ish - good enough for v1); if nobody's
@@ -157,6 +183,15 @@ class PartyServiceClass {
     party.lastActivityUtc = Date.now();
     MusicQueueService.removeVote(party, userId); // no-op for a video party (party.music is unset)
     CastTokenService.revokeForMember(party.id, userId); // no-op if they never cast - see its own comment for why this runs unconditionally, not just on an explicit "stop casting"
+    // No-op if they never had a live Emby Sessions-API entry (never
+    // connected, or the periodic sweep hadn't reached them yet) - see
+    // EmbySessionService's own comment. Fire-and-forget, same as every
+    // other per-member Emby report in this app - it already swallows its
+    // own failures, and leaving the party must never wait on Emby.
+    if (leavingMember?.embyToken && leavingMember.embySession) {
+      const s = leavingMember.embySession;
+      EmbySessionService.stop(leavingMember.embyToken, s.itemId, s.mediaSourceId, s.playSessionId, leavingMember.positionTicks);
+    }
 
     let newHostUserId: string | null = party.hostUserId;
     if (wasHost) {
@@ -175,6 +210,7 @@ class PartyServiceClass {
       MusicQueueService.destroy(party); // clears the auto-advance timer, if any - see its own comment
       TranscodeService.endSession(party.id); // no-op if this party never had a burn-in stream running
       PartyStreamService.endSession(party.id); // same - no-op if this party never negotiated a shared stream
+      if (party.staticLink) StaticPartyService.onPartyDestroyed(party.staticLink, party.id);
       Logger.party(`destroyed partyId=${party.id} (last member ${whoLeft} left)`);
     } else if (wasHost && newHostUserId != null) {
       const newHost = party.members.get(newHostUserId)!;
@@ -196,7 +232,9 @@ class PartyServiceClass {
     if (party.queueIndex >= party.queue.length - 1) {
       return false;
     }
-    const outgoingItemId = party.itemId; // whatever was just playing - see the markPlayed loop below
+    // Whatever was just playing is "done" - before the party's own state
+    // moves on. See completeCurrentItem's own comment.
+    this.completeCurrentItem(party);
     party.queueIndex += 1;
     const next = party.queue[party.queueIndex]!;
     party.itemId = next.itemId;
@@ -207,18 +245,6 @@ class PartyServiceClass {
       member.isPaused = false;
       member.lastUpdatedUtc = Date.now();
     }
-    // The party moving on from `outgoingItemId` is this app's own signal
-    // that it's "done" - see PlaystateService.markPlayed's own comment
-    // for why that's a heuristic, not a real "watched it all" check, and
-    // why every currently-connected member gets their own account
-    // updated, not just the host. Fire-and-forget, same as the periodic
-    // position sync in index.ts - a member's bad token or a transient
-    // Emby hiccup here must never block the party from actually moving
-    // on to the next item.
-    for (const member of party.members.values()) {
-      if (!member.connection || !member.embyToken) continue;
-      PlaystateService.markPlayed(member.embyToken, member.userId, outgoingItemId);
-    }
     // A new item's own MediaStreams indices have nothing to do with the
     // old one's - carrying a burn-in or text subtitle pick across would
     // show whatever track happens to share that index on the new item,
@@ -243,6 +269,40 @@ class PartyServiceClass {
     return true;
   }
 
+  /**
+   * Marks the party's current item as "done": the party moving on from it
+   * (advanceQueue) or the last queued item playing to its end (the host's
+   * "itemEnded" - see SocketGateway) is this app's own signal for that -
+   * see PlaystateService.markPlayed's own comment for why it's a
+   * heuristic, not a real "watched it all" check, and why every
+   * currently-connected member gets their own account updated, not just
+   * the host. Fire-and-forget, same as the periodic position sync in
+   * index.ts - a member's bad token or a transient Emby hiccup here must
+   * never block the party from actually moving on.
+   *
+   * For a session of a static watch party, also records the item as
+   * completed there (StaticPartyService.onItemCompleted) for every
+   * connected member. Idempotent per item (`lastCompletedItemId`), so an
+   * "itemEnded" and a later "next" on the same item never count twice.
+   */
+  completeCurrentItem(party: Party): void {
+    const itemId = party.itemId;
+    if (party.lastCompletedItemId === itemId) return;
+    party.lastCompletedItemId = itemId;
+    const connected = Array.from(party.members.values()).filter((m) => !!m.connection);
+    for (const member of connected) {
+      if (!member.embyToken) continue;
+      PlaystateService.markPlayed(member.embyToken, member.userId, itemId);
+    }
+    if (party.staticLink) {
+      StaticPartyService.onItemCompleted(
+        party.staticLink,
+        itemId,
+        connected.map((m) => ({ userId: m.userId, userName: m.userName }))
+      );
+    }
+  }
+
   /** All active parties - powers the "watch parties en cours" home section. */
   listActive(): Party[] {
     return Array.from(this.partiesById.values());
@@ -256,6 +316,18 @@ class PartyServiceClass {
         MusicQueueService.destroy(party); // same leak this class's own destroy path guards against
         TranscodeService.endSession(party.id); // same leak - see the "leave" destroy path above
         PartyStreamService.endSession(party.id);
+        if (party.staticLink) StaticPartyService.onPartyDestroyed(party.staticLink, party.id);
+        // Same reasoning, for any member whose own "leave" (a clean
+        // disconnect) never fired for whatever reason - a real gap would
+        // otherwise leave a stale entry sitting in Emby's own dashboard
+        // indefinitely, not just until the next sweep tick the way a
+        // still-connected member's stale Progress report would.
+        for (const member of party.members.values()) {
+          if (member.embyToken && member.embySession) {
+            const s = member.embySession;
+            EmbySessionService.stop(member.embyToken, s.itemId, s.mediaSourceId, s.playSessionId, member.positionTicks);
+          }
+        }
         const idleMinutes = Math.round((Date.now() - party.lastActivityUtc) / 60000);
         Logger.party(`destroyed partyId=${party.id} (idle ${idleMinutes}min, ${party.members.size} member(s) still connected)`);
       }
@@ -311,7 +383,8 @@ class PartyServiceClass {
       embyToken: null,
       isPaused: true,
       positionTicks: 0,
-      lastUpdatedUtc: Date.now()
+      lastUpdatedUtc: Date.now(),
+      embySession: null
     };
   }
 }

server/src/services/StaticPartyService.ts

@@ -0,0 +1,319 @@
+'use strict';
+
+import crypto from 'crypto';
+import { Logger } from '../Logger';
+import { StaticPartyStore } from './StaticPartyStore';
+import type {
+  PersistedStaticParty,
+  QueueItem,
+  StaticParty,
+  StaticPartyDetailDto,
+  StaticPartyLink,
+  StaticPartyMember,
+  StaticPartySummaryDto
+} from '../types';
+
+/** A connected participant, as reported by a live session. */
+export interface Participant {
+  userId: string;
+  userName: string;
+}
+
+/**
+ * Which of `items` the viewer has missed, in the items' own order: every
+ * item the group already completed, minus what the viewer watched in-app
+ * (`watchedItemIds`) and minus what Emby itself already has as Played for
+ * them (`embyPlayedIds` - watched outside this app, or before this party
+ * existed). Pure - the one rule this whole feature is about, tested on
+ * its own (see staticPartyService.test.ts).
+ */
+export function computeMissedIds(
+  items: QueueItem[],
+  completedItemIds: string[],
+  watchedItemIds: string[],
+  embyPlayedIds: ReadonlySet<string>
+): string[] {
+  const completed = new Set(completedItemIds);
+  const watched = new Set(watchedItemIds);
+  return items
+    .map((i) => i.itemId)
+    .filter((id) => completed.has(id) && !watched.has(id) && !embyPlayedIds.has(id));
+}
+
+/**
+ * Merges a freshly fetched item list into a static party's existing one:
+ * keeps the existing order and every existing item (even one since
+ * removed from the source - the group's history shouldn't lose it),
+ * refreshes names/images, and appends anything new (a new episode, a
+ * playlist addition) at the end in the source's own order. Returns the
+ * merged list and how many items were added. Pure.
+ */
+export function mergeItemLists(existing: QueueItem[], fresh: QueueItem[]): { items: QueueItem[]; added: number } {
+  const freshById = new Map(fresh.map((i) => [i.itemId, i]));
+  const known = new Set(existing.map((i) => i.itemId));
+  const items = existing.map((i) => freshById.get(i.itemId) ?? i);
+  const additions = fresh.filter((i) => !known.has(i.itemId));
+  return { items: items.concat(additions), added: additions.length };
+}
+
+/**
+ * Static (persistent) watch parties - a whole series or video playlist a
+ * group watches together over several sessions. Remembers the group's own
+ * progress (which items it completed, where it stopped) and each member's
+ * own (which items they watched), so someone coming back or joining late
+ * sees exactly what they missed. See spec/static-watch-party.md.
+ *
+ * A static party never plays anything itself: each session is an
+ * ordinary live Party (PartyService), created by index.ts and linked back
+ * here through `party.staticLink` - so the player, sync, shared stream,
+ * lobby and host handoff are all reused as-is. This service never imports
+ * PartyService (PartyService calls into this one), keeping the dependency
+ * one-way.
+ *
+ * Persisted through StaticPartyStore after every change - one file per
+ * party, so only the party that changed is ever rewritten.
+ */
+class StaticPartyServiceClass {
+  /** Every static party, by id. */
+  private partiesById = new Map<string, StaticParty>();
+
+  /** Loads every persisted party - once, at startup. */
+  public init(): void {
+    this.partiesById.clear();
+    for (const persisted of StaticPartyStore.load()) {
+      this.partiesById.set(persisted.id, { ...persisted, livePartyId: null });
+    }
+  }
+
+  /** Every static party, most recently active first. */
+  public list(): StaticParty[] {
+    return Array.from(this.partiesById.values()).sort((a, b) => this.lastActivity(b) - this.lastActivity(a));
+  }
+
+  /** One static party, or null. */
+  public getById(id: string): StaticParty | null {
+    return this.partiesById.get(id) || null;
+  }
+
+  /** Creates a static party over `items` - the creator is its first member. */
+  public create(
+    creator: Participant,
+    source: StaticParty['source'],
+    name: string,
+    imageUrl: string,
+    items: QueueItem[]
+  ): StaticParty {
+    const now = Date.now();
+    const sp: StaticParty = {
+      id: crypto.randomUUID(),
+      name,
+      source,
+      imageUrl,
+      createdByUserId: creator.userId,
+      createdUtc: now,
+      items,
+      group: { nextIndex: 0, resumePositionTicks: 0, completedItemIds: [], lastSessionUtc: null },
+      members: {},
+      livePartyId: null
+    };
+    sp.members[creator.userId] = this.newMember(creator);
+    this.partiesById.set(sp.id, sp);
+    Logger.staticParty(`created id=${sp.id} name="${name}" source=${source.type}:${source.sourceId} items=${items.length} by=${Logger.who(creator.userId, creator.userName)}`);
+    this.persist(sp);
+    return sp;
+  }
+
+  /** Adds `who` as a member - idempotent (refreshes their name only). */
+  public join(sp: StaticParty, who: Participant): StaticPartyMember {
+    const existing = sp.members[who.userId];
+    if (existing) {
+      existing.userName = who.userName;
+      existing.lastSeenUtc = Date.now();
+      this.persist(sp);
+      return existing;
+    }
+    const member = this.newMember(who);
+    sp.members[who.userId] = member;
+    Logger.staticParty(`joined id=${sp.id} user=${Logger.who(who.userId, who.userName)} members=${Object.keys(sp.members).length}`);
+    this.persist(sp);
+    return member;
+  }
+
+  /** Removes a member - and their progress. The party itself stays, even
+   *  empty: only its creator deletes it (see delete()). */
+  public leave(sp: StaticParty, userId: string): void {
+    const member = sp.members[userId];
+    if (!member) return;
+    delete sp.members[userId];
+    Logger.staticParty(`left id=${sp.id} user=${Logger.who(userId, member.userName)} members=${Object.keys(sp.members).length}`);
+    this.persist(sp);
+  }
+
+  /** Deletes the party for good - creator only. Returns false (and does
+   *  nothing) for anyone else. */
+  public delete(sp: StaticParty, userId: string): boolean {
+    if (sp.createdByUserId !== userId) {
+      Logger.staticParty(`delete refused id=${sp.id} user=${userId} (not the creator)`);
+      return false;
+    }
+    this.partiesById.delete(sp.id);
+    Logger.staticParty(`deleted id=${sp.id} name="${sp.name}"`);
+    StaticPartyStore.remove(sp.id);
+    return true;
+  }
+
+  /** Merges a fresh fetch of the source into `sp.items` (see
+   *  mergeItemLists) - new episodes/playlist entries appear at the end. */
+  public refreshItems(sp: StaticParty, fresh: QueueItem[]): void {
+    if (!fresh.length) return;
+    const { items, added } = mergeItemLists(sp.items, fresh);
+    const changed = added > 0 || items.some((item, i) => item !== sp.items[i]);
+    sp.items = items;
+    if (added) Logger.staticParty(`refreshed id=${sp.id} +${added} new item(s), total=${items.length}`);
+    if (changed) this.persist(sp);
+  }
+
+  /** What the group's next session plays: everything from the group's
+   *  next item on. Empty once the group has seen everything. */
+  public groupQueue(sp: StaticParty): QueueItem[] {
+    return sp.items.slice(sp.group.nextIndex);
+  }
+
+  /** Records which live party is the group's current session (or none). */
+  public setLiveParty(sp: StaticParty, partyId: string | null): void {
+    sp.livePartyId = partyId;
+    if (partyId) {
+      sp.group.lastSessionUtc = Date.now();
+      Logger.staticParty(`session started id=${sp.id} partyId=${partyId} at item ${sp.group.nextIndex + 1}/${sp.items.length}`);
+      this.persist(sp);
+    }
+  }
+
+  /**
+   * A linked live session finished `itemId` (played to its end, or the
+   * host moved past it - the same heuristic as PlaystateService.markPlayed).
+   * Every connected participant gets it as watched (and becomes a member
+   * if they joined the live session without joining the static party
+   * first). In `group` mode the group itself also moves past it; in
+   * `catchUp` mode only those participants' own progress changes.
+   */
+  public onItemCompleted(link: StaticPartyLink, itemId: string, connected: Participant[]): void {
+    const sp = this.partiesById.get(link.staticPartyId);
+    if (!sp) return; // deleted while a session was still running
+    for (const who of connected) {
+      const member = sp.members[who.userId] ?? (sp.members[who.userId] = this.newMember(who));
+      member.lastSeenUtc = Date.now();
+      if (!member.watchedItemIds.includes(itemId)) member.watchedItemIds.push(itemId);
+    }
+    if (link.mode === 'group') {
+      if (!sp.group.completedItemIds.includes(itemId)) sp.group.completedItemIds.push(itemId);
+      const index = sp.items.findIndex((i) => i.itemId === itemId);
+      if (index >= 0 && index + 1 > sp.group.nextIndex) sp.group.nextIndex = index + 1;
+      sp.group.resumePositionTicks = 0;
+    }
+    Logger.staticParty(`item completed id=${sp.id} mode=${link.mode} item=${itemId} by=[${connected.map((c) => c.userName).join(', ')}] group=${sp.group.completedItemIds.length}/${sp.items.length}`);
+    this.persist(sp);
+  }
+
+  /** The group session's current position - saved so the next session
+   *  resumes there. Ignored for anything but the group's next item. */
+  public recordPosition(link: StaticPartyLink, itemId: string, positionTicks: number): void {
+    if (link.mode !== 'group') return;
+    const sp = this.partiesById.get(link.staticPartyId);
+    if (!sp || sp.items[sp.group.nextIndex]?.itemId !== itemId) return;
+    if (sp.group.resumePositionTicks === positionTicks) return;
+    sp.group.resumePositionTicks = positionTicks;
+    this.persist(sp);
+  }
+
+  /** A linked live party ended - forget it as the group's live session. */
+  public onPartyDestroyed(link: StaticPartyLink, partyId: string): void {
+    const sp = this.partiesById.get(link.staticPartyId);
+    if (!sp || sp.livePartyId !== partyId) return;
+    sp.livePartyId = null;
+    Logger.staticParty(`session ended id=${sp.id} partyId=${partyId} resumeAt=item ${sp.group.nextIndex + 1} ${Math.round(sp.group.resumePositionTicks / 10000000)}s`);
+    this.persist(sp);
+  }
+
+  /** "Marquer comme vu" - `who` becomes a member if they weren't yet. */
+  public markWatched(sp: StaticParty, who: Participant, itemId: string): boolean {
+    if (!sp.items.some((i) => i.itemId === itemId)) return false;
+    const member = sp.members[who.userId] ?? (sp.members[who.userId] = this.newMember(who));
+    if (!member.watchedItemIds.includes(itemId)) member.watchedItemIds.push(itemId);
+    member.lastSeenUtc = Date.now();
+    Logger.staticParty(`marked watched id=${sp.id} user=${Logger.who(who.userId, who.userName)} item=${itemId}`);
+    this.persist(sp);
+    return true;
+  }
+
+  /** `viewerUserId`'s missed items - see computeMissedIds. */
+  public missedIds(sp: StaticParty, viewerUserId: string, embyPlayedIds: ReadonlySet<string>): string[] {
+    const watched = sp.members[viewerUserId]?.watchedItemIds ?? [];
+    return computeMissedIds(sp.items, sp.group.completedItemIds, watched, embyPlayedIds);
+  }
+
+  /** The list-view shape of `sp` for `viewerUserId`. `livePartyId` is
+   *  passed in already checked against PartyService (still alive). */
+  public toSummary(sp: StaticParty, viewerUserId: string, embyPlayedIds: ReadonlySet<string>, livePartyId: string | null): StaticPartySummaryDto {
+    return {
+      id: sp.id,
+      name: sp.name,
+      sourceType: sp.source.type,
+      imageUrl: sp.imageUrl,
+      itemCount: sp.items.length,
+      groupWatchedCount: sp.group.completedItemIds.length,
+      nextItemName: sp.items[sp.group.nextIndex]?.itemName ?? null,
+      memberCount: Object.keys(sp.members).length,
+      youAreMember: !!sp.members[viewerUserId],
+      youAreCreator: sp.createdByUserId === viewerUserId,
+      missedCount: this.missedIds(sp, viewerUserId, embyPlayedIds).length,
+      livePartyId
+    };
+  }
+
+  /** The detail-view shape of `sp` for `viewerUserId`. */
+  public toDetail(sp: StaticParty, viewerUserId: string, embyPlayedIds: ReadonlySet<string>, livePartyId: string | null): StaticPartyDetailDto {
+    const completed = new Set(sp.group.completedItemIds);
+    const viewerWatched = new Set(sp.members[viewerUserId]?.watchedItemIds ?? []);
+    return {
+      ...this.toSummary(sp, viewerUserId, embyPlayedIds, livePartyId),
+      items: sp.items.map((item, index) => ({
+        ...item,
+        groupState: completed.has(item.itemId) ? 'watched' : index === sp.group.nextIndex ? 'next' : 'upcoming',
+        viewerWatched: viewerWatched.has(item.itemId) || embyPlayedIds.has(item.itemId)
+      })),
+      missedItemIds: this.missedIds(sp, viewerUserId, embyPlayedIds),
+      members: Object.values(sp.members).map((m) => ({
+        userId: m.userId,
+        userName: m.userName,
+        watchedCount: m.watchedItemIds.length,
+        isCreator: m.userId === sp.createdByUserId
+      }))
+    };
+  }
+
+  /** Writes `sp`'s own file (debounced - see StaticPartyStore). Only the
+   *  party that changed is ever rewritten. */
+  private persist(sp: StaticParty): void {
+    StaticPartyStore.save(sp.id, () => this.snapshotOf(sp));
+  }
+
+  /** `sp` minus runtime-only state. */
+  private snapshotOf(sp: StaticParty): PersistedStaticParty {
+    const { livePartyId: _live, ...persisted } = sp;
+    return persisted;
+  }
+
+  /** When `sp` last saw anything happen - for list ordering. */
+  private lastActivity(sp: StaticParty): number {
+    return Math.max(sp.createdUtc, sp.group.lastSessionUtc ?? 0);
+  }
+
+  /** A fresh member record for `who`. */
+  private newMember(who: Participant): StaticPartyMember {
+    const now = Date.now();
+    return { userId: who.userId, userName: who.userName, joinedUtc: now, watchedItemIds: [], lastSeenUtc: now };
+  }
+}
+
+export const StaticPartyService = new StaticPartyServiceClass();

server/src/services/StaticPartyStore.ts

@@ -0,0 +1,272 @@
+'use strict';
+
+import fs from 'fs';
+import path from 'path';
+import { Logger } from '../Logger';
+import type { PersistedStaticParty } from '../types';
+
+/** One party's own file - versioned so a future format change can migrate
+ *  instead of silently misreading an older file. */
+interface StaticPartyFile {
+  version: 1;
+  party: PersistedStaticParty;
+}
+
+/** The first release's single-file format - only read once, to migrate. */
+interface LegacyStaticPartiesFile {
+  version: 1;
+  parties: PersistedStaticParty[];
+}
+
+/** How long a save waits for more changes to the same party before
+ *  writing - progress updates arrive in bursts (a whole party's members
+ *  at once, the 20s position sweep). */
+const SAVE_DEBOUNCE_MS = 2000;
+
+/** Party ids become file names - anything else is refused outright, so a
+ *  crafted id can never reach outside the directory. */
+const SAFE_ID = /^[A-Za-z0-9-]+$/;
+
+/**
+ * The static watch parties' persistence: **one JSON file per party**,
+ * `${DATA_DIR}/static-parties/<id>.json` - the first and only thing this
+ * app keeps on disk (everything else is deliberately in-memory - see
+ * docs/architecture.md's "Party lifecycle").
+ *
+ * One file per party (rather than a single file for all of them) limits
+ * what any one problem can damage: a write only ever touches the party
+ * that changed, and a corrupt file costs that one party, never the rest.
+ * Each write is also atomic (a `.tmp` sibling, then a rename over the
+ * real file), so a crash mid-write leaves the previous version intact.
+ *
+ * Writes are debounced per party (SAVE_DEBOUNCE_MS). A corrupt file is
+ * logged and moved aside (`.corrupt`) rather than overwritten or
+ * silently dropped - the server must never refuse to start over one, and
+ * nothing is lost for good. The first release's single
+ * `static-parties.json` is migrated once, on the first load that finds it.
+ *
+ * JSON files rather than a database: the data is tiny, the runtime image
+ * is Node 20 (no built-in `node:sqlite`), and a native SQLite binding would
+ * be the image's first compiled dependency - not worth it at this size.
+ */
+class StaticPartyStoreClass {
+  /** `${DATA_DIR}/static-parties` - see configure(). */
+  private dir: string | null = null;
+  /** The first release's single file, migrated on load if still present. */
+  private legacyFile: string | null = null;
+  /** Pending debounced saves, by party id. */
+  private timers = new Map<string, NodeJS.Timeout>();
+  /** What each pending save will write - always the latest snapshot. */
+  private pending = new Map<string, () => PersistedStaticParty>();
+
+  /** Points the store at `dataDir`. Must be called before anything else -
+   *  index.ts does it at startup, tests with a temp directory. */
+  public configure(dataDir: string): void {
+    this.dir = path.resolve(dataDir, 'static-parties');
+    this.legacyFile = path.resolve(dataDir, 'static-parties.json');
+  }
+
+  /** Reads every persisted party - synchronous, startup-only. */
+  public load(): PersistedStaticParty[] {
+    const dir = this.requireDir();
+    try {
+      fs.mkdirSync(dir, { recursive: true });
+    } catch (err) {
+      Logger.staticParty(`could not create ${dir} - starting empty: ${(err as Error).message}`);
+      return [];
+    }
+    this.migrateLegacyFile();
+
+    let names: string[];
+    try {
+      names = fs.readdirSync(dir);
+    } catch (err) {
+      Logger.staticParty(`could not list ${dir} - starting empty: ${(err as Error).message}`);
+      return [];
+    }
+
+    const parties: PersistedStaticParty[] = [];
+    for (const name of names) {
+      const file = path.join(dir, name);
+      if (name.endsWith('.tmp')) {
+        // A write interrupted before its rename - the real file next to it
+        // (if any) is still the last complete version.
+        this.tryUnlink(file);
+        continue;
+      }
+      if (!name.endsWith('.json')) continue; // .corrupt files and anything else
+      const party = this.readPartyFile(file);
+      if (party) parties.push(party);
+    }
+    Logger.staticParty(`loaded ${parties.length} static party(ies) from ${dir}`);
+    return parties;
+  }
+
+  /** Schedules a debounced write of `id`'s own file, from whatever
+   *  `snapshot` returns at write time (so a burst of changes only ever
+   *  writes the final state). */
+  public save(id: string, snapshot: () => PersistedStaticParty): void {
+    if (!SAFE_ID.test(id)) {
+      Logger.staticParty(`save refused: unsafe id "${id}"`);
+      return;
+    }
+    this.pending.set(id, snapshot);
+    if (this.timers.has(id)) return;
+    const timer = setTimeout(() => {
+      this.timers.delete(id);
+      this.writeOne(id).catch((err: unknown) => {
+        Logger.staticParty(`save failed id=${id}: ${(err as Error).message}`);
+      });
+    }, SAVE_DEBOUNCE_MS);
+    timer.unref(); // a pending save must never keep a test process (or a shutdown) alive
+    this.timers.set(id, timer);
+  }
+
+  /** Deletes `id`'s file - and cancels any save still pending for it, so
+   *  a debounced write can't recreate a party that was just deleted. */
+  public remove(id: string): void {
+    const timer = this.timers.get(id);
+    if (timer) clearTimeout(timer);
+    this.timers.delete(id);
+    this.pending.delete(id);
+    if (!SAFE_ID.test(id)) return;
+    const file = this.fileFor(id);
+    try {
+      fs.unlinkSync(file);
+      Logger.staticParty(`removed ${file}`);
+    } catch (err) {
+      if ((err as NodeJS.ErrnoException).code !== 'ENOENT') {
+        Logger.staticParty(`could not remove ${file}: ${(err as Error).message}`);
+      }
+    }
+  }
+
+  /** Writes every pending save immediately and synchronously - for a
+   *  graceful shutdown (SIGTERM/SIGINT), where an async write could be cut
+   *  short by the process exiting. */
+  public flushSync(): void {
+    for (const timer of this.timers.values()) clearTimeout(timer);
+    this.timers.clear();
+    const pending = Array.from(this.pending.entries());
+    this.pending.clear();
+    for (const [id, snapshot] of pending) {
+      const file = this.fileFor(id);
+      try {
+        fs.mkdirSync(path.dirname(file), { recursive: true });
+        fs.writeFileSync(`${file}.tmp`, this.serialize(snapshot()), 'utf8');
+        fs.renameSync(`${file}.tmp`, file);
+      } catch (err) {
+        Logger.staticParty(`flush failed id=${id}: ${(err as Error).message}`);
+      }
+    }
+    if (pending.length) Logger.staticParty(`flushed ${pending.length} static party(ies)`);
+  }
+
+  /** Writes every pending save now (async) - lets tests wait for disk. */
+  public async writeNow(): Promise<void> {
+    for (const timer of this.timers.values()) clearTimeout(timer);
+    this.timers.clear();
+    const ids = Array.from(this.pending.keys());
+    try {
+      await Promise.all(ids.map((id) => this.writeOne(id)));
+    } catch (err) {
+      Logger.staticParty(`writeNow failed: ${(err as Error).message}`);
+      throw err;
+    }
+  }
+
+  /** Writes `id`'s pending snapshot - atomically, via a `.tmp` rename. */
+  private async writeOne(id: string): Promise<void> {
+    const snapshot = this.pending.get(id);
+    if (!snapshot) return;
+    this.pending.delete(id);
+    const file = this.fileFor(id);
+    try {
+      await fs.promises.mkdir(path.dirname(file), { recursive: true });
+      await fs.promises.writeFile(`${file}.tmp`, this.serialize(snapshot()), 'utf8');
+      await fs.promises.rename(`${file}.tmp`, file);
+    } catch (err) {
+      Logger.staticParty(`write to ${file} failed: ${(err as Error).message}`);
+      throw err;
+    }
+  }
+
+  /** One party file's content, or null (moved aside) if it's unreadable. */
+  private readPartyFile(file: string): PersistedStaticParty | null {
+    try {
+      const parsed = JSON.parse(fs.readFileSync(file, 'utf8')) as Partial<StaticPartyFile>;
+      const party = parsed?.party;
+      if (!party || typeof party.id !== 'string' || !Array.isArray(party.items)) {
+        throw new Error('missing or malformed "party"');
+      }
+      if (path.basename(file) !== `${party.id}.json`) throw new Error(`file name does not match id ${party.id}`);
+      return party;
+    } catch (err) {
+      Logger.staticParty(`corrupt file ${file} - moved aside to .corrupt, skipped: ${(err as Error).message}`);
+      try {
+        fs.renameSync(file, `${file}.corrupt`);
+      } catch (renameErr) {
+        Logger.staticParty(`could not move corrupt file aside: ${(renameErr as Error).message}`);
+      }
+      return null;
+    }
+  }
+
+  /**
+   * The first release kept every party in one `static-parties.json` -
+   * split it into one file per party, then rename it to `.migrated` (kept,
+   * not deleted, in case anything went wrong). A party that already has
+   * its own file is left alone: that file is newer.
+   */
+  private migrateLegacyFile(): void {
+    const legacy = this.legacyFile!;
+    if (!fs.existsSync(legacy)) return;
+    try {
+      const parsed = JSON.parse(fs.readFileSync(legacy, 'utf8')) as Partial<LegacyStaticPartiesFile>;
+      const parties = Array.isArray(parsed?.parties) ? parsed.parties : [];
+      let migrated = 0;
+      for (const party of parties) {
+        if (!party || typeof party.id !== 'string' || !SAFE_ID.test(party.id)) continue;
+        const file = this.fileFor(party.id);
+        if (fs.existsSync(file)) continue;
+        fs.writeFileSync(`${file}.tmp`, this.serialize(party), 'utf8');
+        fs.renameSync(`${file}.tmp`, file);
+        migrated++;
+      }
+      fs.renameSync(legacy, `${legacy}.migrated`);
+      Logger.staticParty(`migrated ${migrated} static party(ies) from ${legacy} to one file each (original kept as .migrated)`);
+    } catch (err) {
+      Logger.staticParty(`could not migrate ${legacy} - left in place: ${(err as Error).message}`);
+    }
+  }
+
+  /** `id`'s own file path. */
+  private fileFor(id: string): string {
+    return path.join(this.requireDir(), `${id}.json`);
+  }
+
+  /** A party file's JSON text. */
+  private serialize(party: PersistedStaticParty): string {
+    const data: StaticPartyFile = { version: 1, party };
+    return JSON.stringify(data, null, 2);
+  }
+
+  /** Best-effort delete - logs anything but "already gone". */
+  private tryUnlink(file: string): void {
+    try {
+      fs.unlinkSync(file);
+    } catch (err) {
+      if ((err as NodeJS.ErrnoException).code !== 'ENOENT') {
+        Logger.staticParty(`could not remove ${file}: ${(err as Error).message}`);
+      }
+    }
+  }
+
+  /** The configured directory - throws if configure() was never called. */
+  private requireDir(): string {
+    if (!this.dir) throw new Error('StaticPartyStore.configure() was never called');
+    return this.dir;
+  }
+}
+
+export const StaticPartyStore = new StaticPartyStoreClass();

server/src/types.ts

@@ -29,8 +29,18 @@ export interface ClientToServerEvents {
   join: (msg: { partyId: string; deviceId: string; force?: boolean }) => void;
   playstate: (msg: { isPaused: boolean; positionTicks: number }) => void;
   next: () => void;
+  /** Host-only (checked server-side exactly like "next") - the last
+   *  queued item played to its end, so there's no "next" to send. Lets
+   *  the server count that final item as completed (PartyService
+   *  .completeCurrentItem) without advancing anything. */
+  itemEnded: () => void;
   voteSkip: () => void;
   musicPlaystate: (msg: { isPaused: boolean }) => void;
+  /** No host check, same as "musicPlaystate" - see MusicQueueService's own
+   *  class comment on why a seek gets the same permissive treatment as
+   *  pause/resume (reversible, doesn't change what's playing) rather than
+   *  "voteSkip"'s majority-vote gate (which does). */
+  musicSeek: (msg: { positionSeconds: number }) => void;
   requestPause: () => void;
   requestResume: () => void;
   /** Host-only (checked server-side exactly like "next") - picks which
@@ -152,11 +162,19 @@ declare global {
 export interface EmbyItem {
   Id: string;
   Name: string;
+  /** Emby's own sort key - articles ("The", "Le", "L'", ...) stripped,
+   *  diacritics/case normalized its own way. Only present when a caller's
+   *  `Fields` actually asks for it (getLibraryItems/getArtists do, for
+   *  the library alphabet index - see ItemDto.sortName and
+   *  CatalogService.toItemDto). */
+  SortName?: string;
   Overview?: string;
   ProductionYear?: number;
   Type?: string;
   SeriesId?: string;
   SeriesName?: string;
+  /** An episode's own season - see CatalogService.seasonQueue. */
+  SeasonId?: string;
   ParentIndexNumber?: number;
   IndexNumber?: number;
   RunTimeTicks?: number;
@@ -169,6 +187,11 @@ export interface EmbyItem {
    *  one sampled 500'd), only its album does - this is how an image URL
    *  falls back to the album's art instead. */
   AlbumId?: string;
+  /** The requesting user's own per-item state - Emby embeds it on every
+   *  item fetched with a userId, unasked (see PlaystateService's own
+   *  comment). Only `Played` is read, by the static watch party's
+   *  "missed items" computation (StaticPartyService). */
+  UserData?: { Played?: boolean };
 }
 
 /** This app's own DTO shape - what toItemDto() in CatalogService produces,
@@ -178,6 +201,16 @@ export interface EmbyItem {
 export interface ItemDto {
   id: string;
   name: string;
+  /** Emby's own SortName when the caller requested it, the display name
+   *  otherwise (CatalogService.toItemDto always falls back) - same
+   *  "populated where it matters, harmless default elsewhere" shape as
+   *  durationTicks/indexNumber below. Only client/src/alphaIndex.ts reads
+   *  this today, to bucket a library by letter the same way Emby itself
+   *  already ordered it: Emby's SortName strips leading articles (e.g.
+   *  "Le Voyage" sorts as "Voyage"), so bucketing by the raw display name
+   *  instead put a "L" header in the middle of a "V" run - reported
+   *  directly as headers landing in no sensible order at all. */
+  sortName: string;
   overview?: string;
   year?: number;
   type?: string;
@@ -219,6 +252,25 @@ export interface PlaybackOptionsDto {
   subtitleTracks: PlaybackTrackOption[];
 }
 
+/**
+ * Emby's own native intro/credits detection (a library's own
+ * EnableMarkerDetection option, run by its "Detect Episode Intros"
+ * scheduled task - confirmed directly against a real server's
+ * /openapi.json: MarkerType is one of Chapter/IntroStart/IntroEnd/
+ * CreditsStart, mixed into the same Chapters array as the auto-generated
+ * per-5-minutes ones). Every field is nullable, independently - the task
+ * may not have reached this item yet, the library may not have the
+ * feature enabled at all (it's per-library, not global), or a real
+ * cold-open episode may genuinely have no IntroStart/IntroEnd. None of
+ * that is an error - see CatalogService.getPlaybackMarkers - a caller
+ * just checks each field for null before offering the matching skip
+ * button. */
+export interface PlaybackMarkersDto {
+  introStartTicks: number | null;
+  introEndTicks: number | null;
+  creditsStartTicks: number | null;
+}
+
 // --- Party (video) -----------------------------------------------------------
 
 /** One entry in a video party's fixed, pre-built queue (a movie/standalone
@@ -255,6 +307,22 @@ export interface PartyMember {
   lastUpdatedUtc: number;
   lastPauseRequestUtc?: number;
   lastResumeRequestUtc?: number;
+  /** This member's own live Emby Sessions-API entry, if one's currently
+   *  open - see EmbySessionService. Null whenever they don't have one
+   *  (not connected/no token yet, or the periodic sweep hasn't started
+   *  one for their current item yet). `itemId` is what the sweep compares
+   *  against on each tick to notice an item change (stop the old
+   *  session, start a fresh one) - `mediaSourceId`/`playSessionId` are
+   *  cached here specifically so a Progress report can reuse them
+   *  without renegotiating PlaybackInfo on every single tick. */
+  embySession: EmbyPlaybackSession | null;
+}
+
+/** See PartyMember.embySession's own comment. */
+export interface EmbyPlaybackSession {
+  itemId: string;
+  mediaSourceId: string;
+  playSessionId: string;
 }
 
 /** The full internal party record - never sent to the client as-is, see
@@ -303,6 +371,25 @@ export interface Party {
    *  MusicBar.ts never had this picker in the first place. */
   streamAudioIndex: string | null;
   streamQuality: string | null;
+  /** Set only for a live session launched from a static watch party (see
+   *  StaticPartyService) - absent for every ordinary party. */
+  staticLink?: StaticPartyLink;
+  /** Kept out of the home page's live lobby list (SocketGateway
+   *  .lobbySnapshot) - a solo catch-up session of a static watch party. */
+  hiddenFromLobby?: boolean;
+  /** The last item this party already reported as completed (see
+   *  PartyService.completeCurrentItem) - guards against an "itemEnded"
+   *  followed by a "next" on the same item counting it twice. */
+  lastCompletedItemId?: string | null;
+}
+
+/** How a live party relates to the static watch party it was launched
+ *  from - `group` is the group's own session (advances the group's
+ *  progress), `catchUp` is someone catching up on items they missed
+ *  (only marks those items watched for whoever was connected). */
+export interface StaticPartyLink {
+  staticPartyId: string;
+  mode: 'group' | 'catchUp';
 }
 
 export interface PublicMember {
@@ -359,6 +446,92 @@ export interface LobbyPartyDto {
   positionTicks: number | null;
   isPaused: boolean | null;
   positionUpdatedUtc: number | null;
+  /** The static watch party this live session belongs to, if any - shown
+   *  as a badge on the home page's lobby card. */
+  staticPartyId: string | null;
+  staticPartyName: string | null;
+}
+
+// --- Static (persistent) watch party ------------------------------------------
+
+/** A lounge party's source: a whole series, one season of it, or a
+ *  video playlist. */
+export type StaticPartySourceType = 'series' | 'season' | 'playlist';
+
+/** One member of a static watch party - persisted, independent of any
+ *  live connection (unlike PartyMember). */
+export interface StaticPartyMember {
+  userId: string;
+  userName: string;
+  joinedUtc: number;
+  /** Items this member watched in-app: with the group, in a catch-up
+   *  session, or marked watched by hand. Emby's own Played flag is
+   *  combined with this at read time, never copied into it. */
+  watchedItemIds: string[];
+  lastSeenUtc: number;
+}
+
+/** The group's own progress through a static watch party's items. */
+export interface StaticPartyGroupProgress {
+  /** Index into `items` of the next item the group will watch. */
+  nextIndex: number;
+  /** Where the group stopped inside items[nextIndex] - applied as the
+   *  host's starting position on the next session. */
+  resumePositionTicks: number;
+  completedItemIds: string[];
+  lastSessionUtc: number | null;
+}
+
+/** A persistent watch party over a whole series or video playlist - see
+ *  StaticPartyService and spec/static-watch-party.md. */
+export interface StaticParty {
+  id: string;
+  name: string;
+  /** What the items come from. A `season` also records its series
+   *  (`seriesId`) and number (`seasonNumber`) - episodes are fetched per
+   *  series, then filtered (see CatalogService.seasonQueue). */
+  source: { type: StaticPartySourceType; sourceId: string; seriesId?: string; seasonNumber?: number };
+  imageUrl: string;
+  createdByUserId: string;
+  createdUtc: number;
+  items: QueueItem[];
+  group: StaticPartyGroupProgress;
+  members: Record<string, StaticPartyMember>;
+  /** Runtime only (never persisted) - the live group session, if any. */
+  livePartyId: string | null;
+}
+
+/** The persisted shape of a StaticParty - everything but runtime state. */
+export type PersistedStaticParty = Omit<StaticParty, 'livePartyId'>;
+
+/** One item of a static watch party, as the client sees it. */
+export interface StaticPartyItemDto extends QueueItem {
+  groupState: 'watched' | 'next' | 'upcoming';
+  /** Whether the viewer has watched it (in-app or Emby's Played flag). */
+  viewerWatched: boolean;
+}
+
+/** GET /api/static-parties list entry. */
+export interface StaticPartySummaryDto {
+  id: string;
+  name: string;
+  sourceType: StaticPartySourceType;
+  imageUrl: string;
+  itemCount: number;
+  groupWatchedCount: number;
+  nextItemName: string | null;
+  memberCount: number;
+  youAreMember: boolean;
+  youAreCreator: boolean;
+  missedCount: number;
+  livePartyId: string | null;
+}
+
+/** GET /api/static-parties/:id - the summary plus every item and member. */
+export interface StaticPartyDetailDto extends StaticPartySummaryDto {
+  items: StaticPartyItemDto[];
+  missedItemIds: string[];
+  members: Array<{ userId: string; userName: string; watchedCount: number; isCreator: boolean }>;
 }
 
 export interface LeaveResult {

server/test/catalogService.test.ts

@@ -4,7 +4,7 @@
 import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
 import type { Request, Response } from 'express';
-import { CatalogService, imageUrlFor, splitPlaylistByMediaType } from '../src/services/CatalogService';
+import { CatalogService, imageUrlFor, seasonQueue, seriesQueueFrom, splitPlaylistByMediaType } from '../src/services/CatalogService';
 import { EmbyClient } from '../src/emby/EmbyClient';
 import type { EmbyItem, EmbySession } from '../src/types';
 
@@ -97,6 +97,18 @@ describe('CatalogService', () => {
     );
   });
 
+  it('getRawItem requests Fields=AlbumId - without it, a track started directly (not via its album) always missed imageUrlFor\'s own fallback', async (t) => {
+    let requestedPath = '';
+    t.mock.method(EmbyClient, 'fetch', async (pathAndQuery: string) => {
+      requestedPath = pathAndQuery;
+      return jsonResponse({ Id: 't1', Name: 'Track', Type: 'Audio', AlbumId: 'al1' });
+    });
+
+    await CatalogService.getRawItem(session, 't1');
+
+    assert.ok(requestedPath.includes('Fields=AlbumId'), requestedPath);
+  });
+
   it('getPlaybackOptions flags an image/bitmap subtitle (PGS) as not text-based, real text subtitles as fine', async (t) => {
     t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({
       MediaSources: [{
@@ -117,6 +129,42 @@ describe('CatalogService', () => {
     assert.equal(options.subtitleTracks.find((t) => t.index === 4)?.isTextBased, true, 'ass is text too');
   });
 
+  it('getPlaybackMarkers picks out Intro/Credits markers by MarkerType, ignoring the auto-generated Chapter ones', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({
+      Chapters: [
+        { StartPositionTicks: 0, Name: 'Chapitre 1', MarkerType: 'Chapter' },
+        { StartPositionTicks: 50000000, MarkerType: 'IntroStart' },
+        { StartPositionTicks: 900000000, MarkerType: 'IntroEnd' },
+        { StartPositionTicks: 3000000000, Name: 'Chapitre 2', MarkerType: 'Chapter' },
+        { StartPositionTicks: 20000000000, MarkerType: 'CreditsStart' }
+      ]
+    }));
+
+    const markers = await CatalogService.getPlaybackMarkers(session, 'item1');
+
+    assert.equal(markers.introStartTicks, 50000000);
+    assert.equal(markers.introEndTicks, 900000000);
+    assert.equal(markers.creditsStartTicks, 20000000000);
+  });
+
+  it('getPlaybackMarkers returns nulls, not an error, when the item has no detected markers at all', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({
+      Chapters: [{ StartPositionTicks: 0, Name: 'Chapitre 1', MarkerType: 'Chapter' }]
+    }));
+
+    const markers = await CatalogService.getPlaybackMarkers(session, 'item1');
+
+    assert.deepEqual(markers, { introStartTicks: null, introEndTicks: null, creditsStartTicks: null });
+  });
+
+  it('getPlaybackMarkers returns nulls when the item has no Chapters field at all', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({}));
+
+    const markers = await CatalogService.getPlaybackMarkers(session, 'item1');
+
+    assert.deepEqual(markers, { introStartTicks: null, introEndTicks: null, creditsStartTicks: null });
+  });
+
   it('proxySubtitle asks Emby for this track as WebVTT, using the negotiated MediaSourceId', async (t) => {
     t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({ MediaSources: [{ Id: 'src7' }] }));
     let capturedTarget = '';
@@ -169,6 +217,35 @@ describe('CatalogService', () => {
     );
   });
 
+  it('negotiatePlaybackSession returns the MediaSourceId/PlaySessionId a Sessions-API report needs', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({
+      MediaSources: [{ Id: 'src1' }],
+      PlaySessionId: 'play1'
+    }));
+
+    const result = await CatalogService.negotiatePlaybackSession(session, 'item1');
+
+    assert.deepEqual(result, { mediaSourceId: 'src1', playSessionId: 'play1' });
+  });
+
+  it('negotiatePlaybackSession returns null, not a throw, when Emby has no media source at all', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({ MediaSources: [], PlaySessionId: 'play1' }));
+
+    assert.equal(await CatalogService.negotiatePlaybackSession(session, 'item1'), null);
+  });
+
+  it('negotiatePlaybackSession returns null when Emby omits PlaySessionId, even with a real source', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => jsonResponse({ MediaSources: [{ Id: 'src1' }] }));
+
+    assert.equal(await CatalogService.negotiatePlaybackSession(session, 'item1'), null);
+  });
+
+  it('negotiatePlaybackSession returns null, not a throw, when the negotiation itself fails', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => new Response(null, { status: 500 }) as unknown as Response);
+
+    assert.equal(await CatalogService.negotiatePlaybackSession(session, 'item1'), null);
+  });
+
   it('getPlaylistItemsRaw asks Emby\'s own /Playlists endpoint, in order', async (t) => {
     let capturedPath = '';
     t.mock.method(EmbyClient, 'fetch', async (path: string) => {
@@ -237,3 +314,34 @@ describe('imageUrlFor', () => {
     assert.equal(imageUrlFor({ Id: 't1', Name: 'Track', Type: 'Audio' }), '/api/catalog/image/t1');
   });
 });
+
+describe('seriesQueueFrom / seasonQueue', () => {
+  const ep = (id: string, season: number, seasonId?: string): EmbyItem => ({ Id: id, Name: id, Type: 'Episode', ParentIndexNumber: season, SeasonId: seasonId });
+  // Emby's own order: specials (season 0) first, then every season in turn.
+  const all = [ep('sp1', 0, 'se0'), ep('s1e1', 1, 'se1'), ep('s1e2', 1, 'se1'), ep('s2e1', 2, 'se2'), ep('s2e2', 2, 'se2')];
+
+  it('the whole series starts at S1E1 - specials sort first and are skipped', () => {
+    assert.deepEqual(seriesQueueFrom(all).map((e) => e.Id), ['s1e1', 's1e2', 's2e1', 's2e2']);
+  });
+
+  it('a series with only specials still queues them', () => {
+    assert.deepEqual(seriesQueueFrom([ep('sp1', 0), ep('sp2', 0)]).map((e) => e.Id), ['sp1', 'sp2']);
+  });
+
+  it('from an episode, queues it and everything after it, across seasons', () => {
+    assert.deepEqual(seriesQueueFrom(all, 's1e2').map((e) => e.Id), ['s1e2', 's2e1', 's2e2']);
+  });
+
+  it('an unknown starting episode yields nothing (the caller falls back to that one item)', () => {
+    assert.deepEqual(seriesQueueFrom(all, 'nope'), []);
+  });
+
+  it('a season queues only its own episodes', () => {
+    assert.deepEqual(seasonQueue(all, { Id: 'se1', IndexNumber: 1 }).map((e) => e.Id), ['s1e1', 's1e2']);
+  });
+
+  it('a season falls back to the season number for episodes without a SeasonId', () => {
+    const noIds = [ep('a', 1), ep('b', 2), ep('c', 2)];
+    assert.deepEqual(seasonQueue(noIds, { Id: 'se2', IndexNumber: 2 }).map((e) => e.Id), ['b', 'c']);
+  });
+});

server/test/embySessionService.test.ts

@@ -0,0 +1,91 @@
+// Exercises EmbySessionService directly against a mocked EmbyClient - no
+// real Emby server involved. Covers the request shape each of the three
+// Sessions-API calls sends and that a failure (a non-ok response, or a
+// thrown error) is swallowed rather than propagated - see the class's
+// own comment for why none of this may ever be allowed to disrupt real
+// playback over an admin-dashboard nicety.
+import { describe, it } from 'node:test';
+import assert from 'node:assert/strict';
+import { EmbySessionService } from '../src/services/EmbySessionService';
+import { EmbyClient } from '../src/emby/EmbyClient';
+
+function okResponse(): Response {
+  return new Response(null, { status: 204 }) as unknown as Response;
+}
+
+describe('EmbySessionService', () => {
+  it('start() POSTs to /Sessions/Playing with the negotiated ids and the given position/pause state', async (t) => {
+    let capturedPath = '';
+    let capturedToken = '';
+    let capturedBody: unknown = null;
+    t.mock.method(EmbyClient, 'fetch', async (path: string, token: string, options: { body?: unknown }) => {
+      capturedPath = path;
+      capturedToken = token;
+      capturedBody = options.body;
+      return okResponse();
+    });
+
+    await EmbySessionService.start('tok1', 'item1', 'src1', 'play1', 12_345, false);
+
+    assert.equal(capturedPath, '/Sessions/Playing');
+    assert.equal(capturedToken, 'tok1');
+    assert.deepEqual(capturedBody, {
+      ItemId: 'item1',
+      MediaSourceId: 'src1',
+      PlaySessionId: 'play1',
+      PositionTicks: 12_345,
+      IsPaused: false,
+      PlayMethod: 'Transcode',
+      CanSeek: true
+    });
+  });
+
+  it('progress() POSTs to /Sessions/Playing/Progress', async (t) => {
+    let capturedPath = '';
+    t.mock.method(EmbyClient, 'fetch', async (path: string) => {
+      capturedPath = path;
+      return okResponse();
+    });
+
+    await EmbySessionService.progress('tok1', 'item1', 'src1', 'play1', 999, true);
+
+    assert.equal(capturedPath, '/Sessions/Playing/Progress');
+  });
+
+  it('stop() POSTs to /Sessions/Playing/Stopped', async (t) => {
+    let capturedPath = '';
+    let capturedBody: unknown = null;
+    t.mock.method(EmbyClient, 'fetch', async (path: string, _token: string, options: { body?: unknown }) => {
+      capturedPath = path;
+      capturedBody = options.body;
+      return okResponse();
+    });
+
+    await EmbySessionService.stop('tok1', 'item1', 'src1', 'play1', 42);
+
+    assert.equal(capturedPath, '/Sessions/Playing/Stopped');
+    assert.deepEqual(capturedBody, { ItemId: 'item1', MediaSourceId: 'src1', PlaySessionId: 'play1', PositionTicks: 42 });
+  });
+
+  it('rounds a fractional PositionTicks rather than sending a non-integer', async (t) => {
+    let capturedBody: { PositionTicks?: number } = {};
+    t.mock.method(EmbyClient, 'fetch', async (_path: string, _token: string, options: { body?: unknown }) => {
+      capturedBody = options.body as { PositionTicks?: number };
+      return okResponse();
+    });
+
+    await EmbySessionService.progress('tok1', 'item1', 'src1', 'play1', 12_345.6, false);
+
+    assert.equal(capturedBody.PositionTicks, 12_346);
+  });
+
+  it('a non-ok response is logged, not thrown', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => new Response(null, { status: 401 }) as unknown as Response);
+    await assert.doesNotReject(() => EmbySessionService.start('tok1', 'item1', 'src1', 'play1', 0, false));
+  });
+
+  it('a thrown network error is logged, not propagated', async (t) => {
+    t.mock.method(EmbyClient, 'fetch', async () => { throw new Error('network down'); });
+    await assert.doesNotReject(() => EmbySessionService.stop('tok1', 'item1', 'src1', 'play1', 0));
+  });
+});

server/test/musicQueueService.test.ts

@@ -49,7 +49,8 @@ function fakeMember(userId: string, userName: string, embyToken: string): PartyM
     embyToken,
     isPaused: false,
     positionTicks: 0,
-    lastUpdatedUtc: Date.now()
+    lastUpdatedUtc: Date.now(),
+    embySession: null
   };
 }
 
@@ -76,6 +77,60 @@ describe('MusicQueueService', () => {
     assert.equal(music(party).queue.length, 1);
   });
 
+  it('addTracks queues a whole batch (an album, a discography) in the given order, behind whatever is already playing', () => {
+    const party = fakeParty('p2b');
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 10_000_000 }, 'u-alice', 'Alice');
+
+    MusicQueueService.addTracks(party, [
+      { itemId: 't2', itemName: 'Track Two', itemImageUrl: '/img/t2', durationTicks: 20_000_000 },
+      { itemId: 't3', itemName: 'Track Three', itemImageUrl: '/img/t3', durationTicks: 30_000_000 }
+    ], 'u-bob', 'Bob');
+
+    assert.equal(music(party).current?.track.itemId, 't1', 'still the track already playing');
+    assert.deepEqual(music(party).queue.map((t) => t.itemId), ['t2', 't3']);
+  });
+
+  it('addTracks auto-starts the first track (and only the first) when the queue was empty', () => {
+    const party = fakeParty('p2c');
+    MusicQueueService.init(party, null, 'u-alice', 'Alice'); // empty queue - nothing playing yet
+
+    MusicQueueService.addTracks(party, [
+      { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 10_000_000 },
+      { itemId: 't2', itemName: 'Track Two', itemImageUrl: '/img/t2', durationTicks: 20_000_000 }
+    ], 'u-alice', 'Alice');
+
+    assert.equal(music(party).current?.track.itemId, 't1', 'the batch\'s own first track starts playing');
+    assert.deepEqual(music(party).queue.map((t) => t.itemId), ['t2']);
+  });
+
+  it('addTracks broadcasts once for the whole batch, not once per track', () => {
+    const party = fakeParty('p2d');
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 10_000_000 }, 'u-alice', 'Alice');
+    let broadcasts = 0;
+    // Same "attach a fresh fake io" pattern socketGateway.test.ts's own
+    // attach() helper uses - MusicQueueService is a singleton, but every
+    // test that cares about broadcasts re-attaches its own fake at the
+    // start rather than resetting afterward, and every test that doesn't
+    // care never looks at this.io's side effects at all.
+    MusicQueueService.attachIo({ to: () => ({ emit: () => { broadcasts++; } }) } as unknown as Parameters<typeof MusicQueueService.attachIo>[0]);
+
+    MusicQueueService.addTracks(party, [
+      { itemId: 't2', itemName: 'Track Two', itemImageUrl: '/img/t2', durationTicks: 20_000_000 },
+      { itemId: 't3', itemName: 'Track Three', itemImageUrl: '/img/t3', durationTicks: 30_000_000 },
+      { itemId: 't4', itemName: 'Track Four', itemImageUrl: '/img/t4', durationTicks: 40_000_000 }
+    ], 'u-bob', 'Bob');
+
+    assert.equal(broadcasts, 1);
+  });
+
+  it('addTracks is a harmless no-op for an empty batch', () => {
+    const party = fakeParty('p2e');
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 10_000_000 }, 'u-alice', 'Alice');
+
+    assert.doesNotThrow(() => MusicQueueService.addTracks(party, [], 'u-alice', 'Alice'));
+    assert.equal(music(party).queue.length, 0);
+  });
+
   it('voteSkip needs a strict majority of connected members, not any count', () => {
     const party = fakeParty('p3');
     MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 10_000_000 }, 'u-alice', 'Alice');
@@ -143,6 +198,67 @@ describe('MusicQueueService', () => {
     MusicQueueService.destroy(party); // avoid leaking this test's own long-duration timer
   });
 
+  it('seek while paused jumps the frozen elapsed time directly, without needing a resume', () => {
+    const party = fakeParty('p4b');
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 600_000_000 /* 60s */ }, 'u-alice', 'Alice');
+    MusicQueueService.setPaused(party, true);
+
+    MusicQueueService.seek(party, 30);
+
+    assert.equal(music(party).current?.isPaused, true, 'seeking must not itself resume playback');
+    assert.equal(MusicQueueService.getElapsedSeconds(party), 30);
+  });
+
+  it('seek clamps into [0, duration] rather than trusting an out-of-range value verbatim', () => {
+    const party = fakeParty('p4c');
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 100_000_000 /* 10s */ }, 'u-alice', 'Alice');
+    MusicQueueService.setPaused(party, true);
+
+    MusicQueueService.seek(party, 999);
+    assert.equal(MusicQueueService.getElapsedSeconds(party), 10, 'clamped to the track\'s own duration');
+
+    MusicQueueService.seek(party, -5);
+    assert.equal(MusicQueueService.getElapsedSeconds(party), 0, 'clamped to zero, not left negative');
+  });
+
+  it('seek while playing re-arms the auto-advance timer against the new position, not the old one', async () => {
+    const party = fakeParty('p4d');
+    // Exactly a 2s track (20_000_000 ticks / 10_000_000 per second - no
+    // rounding to worry about) - seeking to 1.7s leaves ~300ms remaining.
+    // If the timer were left un-re-armed (still counting down from the
+    // original full 2s mark instead), it would still be playing at the
+    // 600ms mark below - comfortably short of the original ~2000ms, so
+    // this genuinely distinguishes the two.
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 20_000_000 }, 'u-alice', 'Alice');
+
+    MusicQueueService.seek(party, 1.7);
+    assert.equal(music(party).current?.track.itemId, 't1', 'still the same track right after seeking');
+
+    await sleep(600); // past the re-armed ~300ms, comfortably short of the original ~2000ms
+    assert.equal(music(party).current, null, 'nothing queued behind it - should have auto-advanced off the re-armed timer');
+  });
+
+  it('seek while playing clears the old timer before scheduling a new one - never double-scheduled', (t) => {
+    const realClearTimeout = global.clearTimeout;
+    const cleared = mock.fn(realClearTimeout);
+    global.clearTimeout = cleared as typeof clearTimeout;
+    t.after(() => { global.clearTimeout = realClearTimeout; });
+
+    const party = fakeParty('p4e');
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 600_000_000 /* 60s - stays pending */ }, 'u-alice', 'Alice');
+
+    MusicQueueService.seek(party, 10);
+
+    assert.equal(cleared.mock.callCount(), 1, 'the pre-seek timer must be cleared, not left running alongside the new one');
+    MusicQueueService.destroy(party); // avoid leaking this test's own long-duration timer
+  });
+
+  it('seek is a harmless no-op when nothing is currently playing', () => {
+    const party = fakeParty('p4f');
+    MusicQueueService.init(party, null, 'u-alice', 'Alice');
+    assert.doesNotThrow(() => MusicQueueService.seek(party, 30));
+  });
+
   it('a short track auto-advances on its own via a real timer, with no client reporting "ended"', async () => {
     const party = fakeParty('p5');
     MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 10_000_000 /* 1s */ }, 'u-alice', 'Alice');

server/test/partyService.test.ts

@@ -4,6 +4,7 @@ import { PartyService } from '../src/services/PartyService';
 import { MusicQueueService } from '../src/services/MusicQueueService';
 import { PlaystateService } from '../src/services/PlaystateService';
 import { CastTokenService } from '../src/services/CastTokenService';
+import { EmbySessionService } from '../src/services/EmbySessionService';
 import type { AppSocket } from '../src/types';
 
 describe('PartyService', () => {
@@ -127,6 +128,68 @@ describe('PartyService', () => {
     assert.deepEqual(calls, [[party.id, 'u-bob']]);
   });
 
+  it('leave() stops whatever Emby Sessions-API entry the leaving member had open', (t) => {
+    const calls: unknown[][] = [];
+    t.mock.method(EmbySessionService, 'stop', async (...args: unknown[]) => { calls.push(args); });
+
+    const party = PartyService.create('u-alice', 'Alice', 'm1', 'Un Film', '/img/m1', null, 'video');
+    const bob = PartyService.join(party, 'u-bob', 'Bob');
+    bob.embyToken = 'tok-bob';
+    bob.positionTicks = 555;
+    bob.embySession = { itemId: 'm1', mediaSourceId: 'src1', playSessionId: 'play1' };
+
+    PartyService.leave(party, 'u-bob');
+
+    assert.deepEqual(calls, [['tok-bob', 'm1', 'src1', 'play1', 555]]);
+  });
+
+  it('leave() does not call EmbySessionService.stop for a member with no open session', (t) => {
+    let called = false;
+    t.mock.method(EmbySessionService, 'stop', async () => { called = true; });
+
+    const party = PartyService.create('u-alice', 'Alice', 'm1', 'Un Film', '/img/m1', null, 'video');
+    PartyService.join(party, 'u-bob', 'Bob'); // embyToken/embySession both still null - see newMember
+
+    PartyService.leave(party, 'u-bob');
+
+    assert.equal(called, false);
+  });
+
+  it('isStaleDevice(): false when the deviceId matches the member\'s own', () => {
+    const party = PartyService.create('u-alice', 'Alice', 'm1', 'Un Film', '/img/m1', null, 'video');
+    const alice = party.members.get('u-alice')!;
+    alice.deviceId = 'device-a';
+
+    assert.equal(PartyService.isStaleDevice(alice, 'device-a'), false);
+  });
+
+  it('isStaleDevice(): true when the deviceId differs from the member\'s own - the actual takeover case', () => {
+    const party = PartyService.create('u-alice', 'Alice', 'm1', 'Un Film', '/img/m1', null, 'video');
+    const alice = party.members.get('u-alice')!;
+    alice.deviceId = 'device-a'; // device B's takeover already moved this forward
+
+    assert.equal(PartyService.isStaleDevice(alice, 'device-b'), true);
+  });
+
+  it('isStaleDevice(): false when the member has no recorded deviceId yet - nothing to conflict with, same reasoning as the socket "join" handler', () => {
+    const party = PartyService.create('u-alice', 'Alice', 'm1', 'Un Film', '/img/m1', null, 'video');
+    const alice = party.members.get('u-alice')!; // deviceId still null - no socket "join" has succeeded yet
+
+    assert.equal(PartyService.isStaleDevice(alice, 'device-a'), false);
+  });
+
+  it('isStaleDevice(): false when the caller sent no deviceId at all - only ever blocks on positive evidence of a mismatch', () => {
+    const party = PartyService.create('u-alice', 'Alice', 'm1', 'Un Film', '/img/m1', null, 'video');
+    const alice = party.members.get('u-alice')!;
+    alice.deviceId = 'device-a';
+
+    assert.equal(PartyService.isStaleDevice(alice, null), false);
+  });
+
+  it('isStaleDevice(): false for an unknown member (already left some other way)', () => {
+    assert.equal(PartyService.isStaleDevice(undefined, 'device-a'), false);
+  });
+
   it('join() is idempotent: re-joining an existing member returns it as-is instead of resetting it', () => {
     const party = PartyService.create('u-alice', 'Alice', 'm1', 'Un Film', '/img/m1', null, 'video');
     const bob = PartyService.join(party, 'u-bob', 'Bob');

server/test/socketGateway.test.ts

@@ -56,7 +56,7 @@ function attach(io: ReturnType<typeof fakeIo>) {
 }
 
 describe('SocketGateway', () => {
-  it('voteSkip/musicPlaystate are no-ops on a video party', () => {
+  it('voteSkip/musicPlaystate/musicSeek are no-ops on a video party', () => {
     const io = fakeIo();
     attach(io);
     const party = PartyService.create('u-host', 'Host', 'm1', 'Un Film', '/img/m1', null, 'video');
@@ -67,7 +67,8 @@ describe('SocketGateway', () => {
     const before = io.roomEmits.length;
     socket.trigger('voteSkip');
     socket.trigger('musicPlaystate', { isPaused: true });
-    assert.equal(io.roomEmits.length, before, 'neither event should produce any broadcast on a video party');
+    socket.trigger('musicSeek', { positionSeconds: 30 });
+    assert.equal(io.roomEmits.length, before, 'none of these events should produce any broadcast on a video party');
   });
 
   it('a non-host member can pause and resume a music party directly (no host check)', () => {
@@ -88,6 +89,23 @@ describe('SocketGateway', () => {
     assert.equal(party.music?.current?.isPaused, false);
   });
 
+  it('a non-host member can seek a music party directly (no host check)', () => {
+    const io = fakeIo();
+    attach(io);
+    const party = PartyService.create('u-alice', 'Alice', 't1', 'Track One', '/img/t1', null, 'music');
+    MusicQueueService.init(party, { itemId: 't1', itemName: 'Track One', itemImageUrl: '/img/t1', durationTicks: 600_000_000 }, 'u-alice', 'Alice');
+    MusicQueueService.setPaused(party, true); // frozen elapsed time makes the resulting position deterministic below
+    PartyService.join(party, 'u-bob', 'Bob');
+
+    const bobSocket = fakeSocket('u-bob');
+    io.trigger('connection', bobSocket as unknown as AppSocket);
+    bobSocket.trigger('join', { partyId: party.id });
+
+    assert.notEqual(party.hostUserId, 'u-bob');
+    bobSocket.trigger('musicSeek', { positionSeconds: 30 });
+    assert.equal(MusicQueueService.getElapsedSeconds(party), 30);
+  });
+
   it('voteSkip needs a majority of connected members and broadcasts queueUpdated on the party room', () => {
     const io = fakeIo();
     attach(io);

server/test/staticPartyService.test.ts

@@ -0,0 +1,299 @@
+import { describe, it, before, beforeEach } from 'node:test';
+import assert from 'node:assert/strict';
+import fs from 'fs';
+import os from 'os';
+import path from 'path';
+import { StaticPartyService, computeMissedIds, mergeItemLists } from '../src/services/StaticPartyService';
+import { StaticPartyStore } from '../src/services/StaticPartyStore';
+import { PartyService } from '../src/services/PartyService';
+import { PlaystateService } from '../src/services/PlaystateService';
+import type { AppSocket, QueueItem } from '../src/types';
+
+const item = (id: string): QueueItem => ({ itemId: id, itemName: `Episode ${id}`, itemImageUrl: `/img/${id}` });
+const ITEMS = ['e1', 'e2', 'e3', 'e4'].map(item);
+const alice = { userId: 'u-alice', userName: 'Alice' };
+const bob = { userId: 'u-bob', userName: 'Bob' };
+const NONE: ReadonlySet<string> = new Set();
+
+let dataDir: string;
+
+before(() => {
+  dataDir = fs.mkdtempSync(path.join(os.tmpdir(), 'wp-static-'));
+  StaticPartyStore.configure(dataDir);
+});
+
+const partiesDir = () => path.join(dataDir, 'static-parties');
+
+beforeEach(() => {
+  StaticPartyStore.flushSync(); // no debounced save from a previous test may land mid-test
+  fs.rmSync(partiesDir(), { recursive: true, force: true });
+  for (const name of fs.readdirSync(dataDir)) fs.rmSync(path.join(dataDir, name), { recursive: true, force: true });
+  StaticPartyService.init();
+});
+
+describe('computeMissedIds', () => {
+  it('is every group-completed item, in the items\' own order', () => {
+    assert.deepEqual(computeMissedIds(ITEMS, ['e2', 'e1'], [], NONE), ['e1', 'e2']);
+  });
+
+  it('drops what the viewer watched in-app and what Emby already has as Played', () => {
+    assert.deepEqual(computeMissedIds(ITEMS, ['e1', 'e2', 'e3'], ['e1'], new Set(['e3'])), ['e2']);
+  });
+
+  it('never lists an item the group has not completed yet, even if the viewer watched ahead', () => {
+    assert.deepEqual(computeMissedIds(ITEMS, ['e1'], ['e4'], NONE), ['e1']);
+  });
+});
+
+describe('mergeItemLists', () => {
+  it('keeps the existing order, appends new items and keeps ones gone from the source', () => {
+    const { items, added } = mergeItemLists([item('e1'), item('e2')], [item('e2'), item('e3')]);
+    assert.deepEqual(items.map((i) => i.itemId), ['e1', 'e2', 'e3']);
+    assert.equal(added, 1);
+  });
+
+  it('refreshes a known item\'s name from the fresh fetch', () => {
+    const { items } = mergeItemLists([item('e1')], [{ ...item('e1'), itemName: 'Renamed' }]);
+    assert.equal(items[0]!.itemName, 'Renamed');
+  });
+});
+
+describe('StaticPartyService', () => {
+  it('create() makes the creator the first member, with nothing watched yet', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    assert.deepEqual(Object.keys(sp.members), ['u-alice']);
+    assert.equal(sp.group.nextIndex, 0);
+    assert.deepEqual(StaticPartyService.groupQueue(sp).map((i) => i.itemId), ['e1', 'e2', 'e3', 'e4']);
+  });
+
+  it('a group completion advances the group and credits only connected participants', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.join(sp, bob);
+    const link = { staticPartyId: sp.id, mode: 'group' as const };
+
+    StaticPartyService.onItemCompleted(link, 'e1', [alice, bob]);
+    StaticPartyService.onItemCompleted(link, 'e2', [alice]); // Bob missed this one
+
+    assert.equal(sp.group.nextIndex, 2);
+    assert.deepEqual(sp.group.completedItemIds, ['e1', 'e2']);
+    assert.deepEqual(StaticPartyService.missedIds(sp, bob.userId, NONE), ['e2']);
+    assert.deepEqual(StaticPartyService.missedIds(sp, alice.userId, NONE), []);
+    assert.deepEqual(StaticPartyService.groupQueue(sp).map((i) => i.itemId), ['e3', 'e4']);
+  });
+
+  it('a late joiner sees everything the group completed before them as missed', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'group' }, 'e1', [alice]);
+    StaticPartyService.join(sp, bob);
+    assert.deepEqual(StaticPartyService.missedIds(sp, bob.userId, NONE), ['e1']);
+  });
+
+  it('a connected participant who never joined the static party becomes a member on completion', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'group' }, 'e1', [alice, bob]);
+    assert.deepEqual(sp.members[bob.userId]!.watchedItemIds, ['e1']);
+  });
+
+  it('a catch-up completion credits the participant without moving the group', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'group' }, 'e1', [alice]);
+    StaticPartyService.join(sp, bob);
+
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'catchUp' }, 'e1', [bob]);
+
+    assert.deepEqual(StaticPartyService.missedIds(sp, bob.userId, NONE), []);
+    assert.equal(sp.group.nextIndex, 1, 'unchanged by a catch-up');
+    assert.deepEqual(sp.group.completedItemIds, ['e1']);
+  });
+
+  it('markWatched removes an item from the missed list, and refuses an unknown item', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'group' }, 'e1', [alice]);
+    assert.equal(StaticPartyService.markWatched(sp, bob, 'e1'), true);
+    assert.deepEqual(StaticPartyService.missedIds(sp, bob.userId, NONE), []);
+    assert.equal(StaticPartyService.markWatched(sp, bob, 'nope'), false);
+  });
+
+  it('recordPosition only keeps a position for the group\'s next item, and a completion resets it', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    const link = { staticPartyId: sp.id, mode: 'group' as const };
+    StaticPartyService.recordPosition(link, 'e3', 999);
+    assert.equal(sp.group.resumePositionTicks, 0, 'not the next item - ignored');
+    StaticPartyService.recordPosition(link, 'e1', 123);
+    assert.equal(sp.group.resumePositionTicks, 123);
+    StaticPartyService.recordPosition({ ...link, mode: 'catchUp' }, 'e1', 456);
+    assert.equal(sp.group.resumePositionTicks, 123, 'a catch-up session never moves the group');
+    StaticPartyService.onItemCompleted(link, 'e1', [alice]);
+    assert.equal(sp.group.resumePositionTicks, 0);
+  });
+
+  it('refreshItems appends new episodes without losing progress', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS.slice(0, 2));
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'group' }, 'e1', [alice]);
+    StaticPartyService.refreshItems(sp, ITEMS);
+    assert.deepEqual(sp.items.map((i) => i.itemId), ['e1', 'e2', 'e3', 'e4']);
+    assert.equal(sp.group.nextIndex, 1);
+    assert.deepEqual(sp.group.completedItemIds, ['e1']);
+  });
+
+  it('only the creator can delete; leaving keeps the party', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.join(sp, bob);
+    assert.equal(StaticPartyService.delete(sp, bob.userId), false);
+    StaticPartyService.leave(sp, bob.userId);
+    assert.ok(StaticPartyService.getById(sp.id));
+    assert.equal(StaticPartyService.delete(sp, alice.userId), true);
+    assert.equal(StaticPartyService.getById(sp.id), null);
+  });
+
+  it('onPartyDestroyed only clears the matching live session', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.setLiveParty(sp, 'p1');
+    StaticPartyService.onPartyDestroyed({ staticPartyId: sp.id, mode: 'catchUp' }, 'p2');
+    assert.equal(sp.livePartyId, 'p1');
+    StaticPartyService.onPartyDestroyed({ staticPartyId: sp.id, mode: 'group' }, 'p1');
+    assert.equal(sp.livePartyId, null);
+  });
+
+  it('toDetail marks each item\'s group state and the viewer\'s own (in-app or Emby Played)', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'group' }, 'e1', [alice]);
+    const detail = StaticPartyService.toDetail(sp, bob.userId, new Set(['e4']), null);
+    assert.deepEqual(detail.items.map((i) => i.groupState), ['watched', 'next', 'upcoming', 'upcoming']);
+    assert.deepEqual(detail.items.map((i) => i.viewerWatched), [false, false, false, true]);
+    assert.deepEqual(detail.missedItemIds, ['e1']);
+    assert.equal(detail.youAreMember, false);
+    assert.equal(detail.missedCount, 1);
+  });
+});
+
+describe('StaticPartyStore', () => {
+  it('writes one file per party, and round-trips it without runtime-only state', async () => {
+    const sp = StaticPartyService.create(alice, { type: 'playlist', sourceId: 'pl1' }, 'Soirées', '/img/pl1', ITEMS);
+    const other = StaticPartyService.create(bob, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    StaticPartyService.onItemCompleted({ staticPartyId: sp.id, mode: 'group' }, 'e1', [alice]);
+    StaticPartyService.setLiveParty(sp, 'live-1');
+    await StaticPartyStore.writeNow();
+
+    assert.deepEqual(fs.readdirSync(partiesDir()).sort(), [`${sp.id}.json`, `${other.id}.json`].sort());
+    const onDisk = JSON.parse(fs.readFileSync(path.join(partiesDir(), `${sp.id}.json`), 'utf8'));
+    assert.equal(onDisk.version, 1);
+    assert.equal('livePartyId' in onDisk.party, false);
+
+    StaticPartyService.init();
+    const reloaded = StaticPartyService.getById(sp.id)!;
+    assert.equal(reloaded.name, 'Soirées');
+    assert.deepEqual(reloaded.group.completedItemIds, ['e1']);
+    assert.equal(reloaded.livePartyId, null, 'a restart ends every live session');
+    assert.ok(StaticPartyService.getById(other.id));
+  });
+
+  it('a change only rewrites the party that changed', async () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'A', '/img/s1', ITEMS);
+    const other = StaticPartyService.create(bob, { type: 'series', sourceId: 's1' }, 'B', '/img/s1', ITEMS);
+    await StaticPartyStore.writeNow();
+    const otherFile = path.join(partiesDir(), `${other.id}.json`);
+    const past = new Date(Date.now() - 60000);
+    fs.utimesSync(otherFile, past, past);
+    // Compared against what the filesystem itself reports back, not
+    // past.getTime(): Linux returns mtimeMs as a float that can land a
+    // hair off the exact millisecond set (e.g. ...780.999 for ...781).
+    const mtimeBefore = fs.statSync(otherFile).mtimeMs;
+
+    StaticPartyService.markWatched(sp, alice, 'e1');
+    await StaticPartyStore.writeNow();
+
+    assert.equal(fs.statSync(otherFile).mtimeMs, mtimeBefore, 'the untouched party\'s file was not rewritten');
+  });
+
+  it('deleting a party removes its file, even with a save still pending', async () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'A', '/img/s1', ITEMS);
+    await StaticPartyStore.writeNow();
+    StaticPartyService.markWatched(sp, alice, 'e1'); // schedules a save...
+    StaticPartyService.delete(sp, alice.userId); // ...that must not recreate the file
+    await StaticPartyStore.writeNow();
+    assert.equal(fs.existsSync(path.join(partiesDir(), `${sp.id}.json`)), false);
+  });
+
+  it('a corrupt file is moved aside and only that party is lost', async () => {
+    const good = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'Good', '/img/s1', ITEMS);
+    await StaticPartyStore.writeNow();
+    fs.writeFileSync(path.join(partiesDir(), 'broken-id.json'), '{ not json', 'utf8');
+
+    StaticPartyService.init();
+
+    assert.deepEqual(StaticPartyService.list().map((p) => p.id), [good.id]);
+    assert.ok(fs.existsSync(path.join(partiesDir(), 'broken-id.json.corrupt')));
+  });
+
+  it('a leftover .tmp from an interrupted write is cleaned up, the real file kept', async () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'A', '/img/s1', ITEMS);
+    await StaticPartyStore.writeNow();
+    fs.writeFileSync(path.join(partiesDir(), `${sp.id}.json.tmp`), '{ half-writ', 'utf8');
+
+    StaticPartyService.init();
+
+    assert.ok(StaticPartyService.getById(sp.id));
+    assert.equal(fs.existsSync(path.join(partiesDir(), `${sp.id}.json.tmp`)), false);
+  });
+
+  it('migrates the first release\'s single static-parties.json into one file per party', () => {
+    const legacy = { version: 1, parties: [
+      { id: 'aaa-1', name: 'One', source: { type: 'series', sourceId: 's1' }, imageUrl: '', createdByUserId: 'u-alice', createdUtc: 1,
+        items: ITEMS, group: { nextIndex: 1, resumePositionTicks: 0, completedItemIds: ['e1'], lastSessionUtc: null }, members: {} },
+      { id: 'bbb-2', name: 'Two', source: { type: 'series', sourceId: 's1' }, imageUrl: '', createdByUserId: 'u-bob', createdUtc: 2,
+        items: ITEMS, group: { nextIndex: 0, resumePositionTicks: 0, completedItemIds: [], lastSessionUtc: null }, members: {} }
+    ] };
+    fs.writeFileSync(path.join(dataDir, 'static-parties.json'), JSON.stringify(legacy), 'utf8');
+
+    StaticPartyService.init();
+
+    assert.deepEqual(StaticPartyService.list().map((p) => p.id).sort(), ['aaa-1', 'bbb-2']);
+    assert.deepEqual(StaticPartyService.getById('aaa-1')!.group.completedItemIds, ['e1']);
+    assert.ok(fs.existsSync(path.join(partiesDir(), 'aaa-1.json')));
+    assert.equal(fs.existsSync(path.join(dataDir, 'static-parties.json')), false);
+    assert.ok(fs.existsSync(path.join(dataDir, 'static-parties.json.migrated')), 'the original is kept, not deleted');
+  });
+
+  it('an empty data directory is a normal first start', () => {
+    StaticPartyService.init();
+    assert.equal(StaticPartyService.list().length, 0);
+  });
+});
+
+describe('PartyService <-> static watch party', () => {
+  const connected = { emit() {}, disconnect() {} } as unknown as AppSocket;
+
+  it('advanceQueue credits the outgoing item to a linked static party, once', (t) => {
+    t.mock.method(PlaystateService, 'markPlayed', async () => {});
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    const party = PartyService.create(alice.userId, alice.userName, 'e1', 'Episode e1', '/img/e1', ITEMS, 'video');
+    party.staticLink = { staticPartyId: sp.id, mode: 'group' };
+    party.members.get(alice.userId)!.connection = connected;
+
+    PartyService.completeCurrentItem(party); // "itemEnded"...
+    PartyService.advanceQueue(party); // ...then "next" on the same item: must not double-count
+
+    assert.deepEqual(sp.group.completedItemIds, ['e1']);
+    assert.deepEqual(sp.members[alice.userId]!.watchedItemIds, ['e1']);
+    assert.equal(sp.group.nextIndex, 1);
+  });
+
+  it('an ordinary party never touches any static party', (t) => {
+    t.mock.method(PlaystateService, 'markPlayed', async () => {});
+    const completed = t.mock.method(StaticPartyService, 'onItemCompleted');
+    const party = PartyService.create(alice.userId, alice.userName, 'e1', 'Episode e1', '/img/e1', ITEMS, 'video');
+    party.members.get(alice.userId)!.connection = connected;
+    PartyService.advanceQueue(party);
+    assert.equal(completed.mock.callCount(), 0);
+  });
+
+  it('the last member leaving a group session clears the static party\'s live session', () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'My Show', '/img/s1', ITEMS);
+    const party = PartyService.create(alice.userId, alice.userName, 'e1', 'Episode e1', '/img/e1', ITEMS, 'video');
+    party.staticLink = { staticPartyId: sp.id, mode: 'group' };
+    StaticPartyService.setLiveParty(sp, party.id);
+    PartyService.leave(party, alice.userId);
+    assert.equal(sp.livePartyId, null);
+  });
+});

spec/static-watch-party.md

@@ -0,0 +1,166 @@
+# Lounge party (watch party statique)
+
+## Les trois types de party
+
+| Nom dans l'interface | Quoi | Où |
+|---|---|---|
+| **Watch party** | party vidéo classique, éphémère | accueil, « Parties en cours » |
+| **Listen party** | party audio classique, éphémère (barre musique) | accueil, « Parties en cours » |
+| **Lounge party** | party statique : une série ou une playlist vidéo suivie sur plusieurs séances | onglet « Lounge parties » |
+
+Côté code, la lounge party reste nommée « static party » (`StaticPartyService`,
+route `/static`, `staticLink`...). Seuls les libellés visibles ont changé. Sur
+l'accueil, chaque carte affiche un badge « Watch party » ou « Listen party ».
+
+## Objectif
+
+Suivre une série entière, ou une playlist vidéo, en groupe sur plusieurs
+soirées. L'app mémorise :
+
+- **l'avancement du groupe** : les éléments terminés ensemble, et où la
+  dernière séance s'est arrêtée ;
+- **l'avancement de chaque personne** : ce qu'elle a vu.
+
+Une personne qui revient ou qui rejoint en cours de route voit la liste de
+ce qu'elle a **manqué** et peut le rattraper.
+
+Contrairement à une watch party classique, qui vit en mémoire et disparaît
+avec son dernier membre, une watch party statique est **persistée sur
+disque** et survit aux redémarrages.
+
+## Modèle
+
+| Entité | Où | Rôle |
+|---|---|---|
+| `StaticParty` | `server/src/types.ts`, persistée | la « saison » du groupe : items, progression du groupe, membres |
+| `StaticPartyMember` | dans `StaticParty.members` | `watchedItemIds` = ce que la personne a vu dans l'app |
+| Séance | une `Party` live ordinaire + `party.staticLink` | la lecture elle-même : lecteur, sync, flux partagé et lobby réutilisés tels quels |
+
+`party.staticLink.mode` :
+
+- `group` : la séance du groupe. Un item terminé fait avancer le groupe
+  **et** est crédité à chaque participant connecté.
+- `catchUp` : un rattrapage. L'item est crédité aux participants connectés
+  uniquement, le groupe ne bouge pas.
+
+`party.hiddenFromLobby` : un rattrapage en solo n'apparaît pas dans la liste
+des watch parties en cours.
+
+## Règles
+
+- **Item terminé** :
+  - l'hôte passe à l'item suivant (`next`),
+  - ou le dernier item de la file se termine (`itemEnded`, nouvel event socket réservé à l'hôte).
+
+  Les deux passent par `PartyService.completeCurrentItem`, qui gère aussi le
+  flag `Played` d'Emby. Un même item n'est jamais compté deux fois de suite
+  (`lastCompletedItemId`). C'est la même heuristique que
+  `PlaystateService.markPlayed` : « le groupe est passé à la suite » vaut
+  « vu ».
+- **Seuls les membres connectés** au moment où l'item se termine sont
+  crédités. Une personne partie en cours d'épisode l'a donc manqué ; elle
+  peut le marquer comme vu.
+- **Manqués d'une personne** : les items terminés par le groupe, dans
+  l'ordre de la liste, moins ceux qu'elle a vus dans l'app
+  (`watchedItemIds`), moins ceux qu'Emby a déjà en `Played` pour son compte
+  (vus ailleurs). C'est la fonction pure `computeMissedIds`.
+- **Reprise** : le sweep existant des 20 s enregistre la position de l'hôte
+  (`group.resumePositionTicks`). La séance suivante démarre avec cette
+  position comme position de l'hôte, que `Player.ts` utilise déjà pour
+  placer la première image.
+- **Nouveaux épisodes** : chaque lecture de la page, et chaque lancement de
+  séance, recharge la source. Les nouveaux items sont ajoutés à la fin ; les
+  items retirés de la source sont conservés dans l'historique
+  (`mergeItemLists`).
+- **Accès** : ouverte à tous les comptes Emby.
+  - Rejoindre = devenir membre. Rejoindre la séance du groupe depuis le
+    lobby rend aussi membre de la watch party statique.
+  - N'importe quel membre peut lancer la séance ; celui qui la lance en
+    devient l'hôte.
+  - Quitter efface sa propre progression.
+  - Seul le créateur peut supprimer la watch party.
+- **Contenus** : une série entière, **une seule saison**, ou une playlist
+  vidéo. Une playlist musicale est refusée.
+  - Série entière : tous les épisodes de toutes les saisons à partir de S1E1.
+    Les spéciaux (saison 0) sont exclus : Emby les trie en premier, et une
+    séance commencerait par eux (`CatalogService.seriesQueueFrom`). Les
+    lounge parties créées avant ce changement gardent leurs spéciaux déjà
+    en liste.
+  - Saison : uniquement les épisodes de cette saison
+    (`CatalogService.seasonQueue`, par `SeasonId`, sinon par numéro de
+    saison). La source garde `seriesId` et `seasonNumber`, car les
+    épisodes sont récupérés par série puis filtrés. Nom par défaut :
+    « Série - Saison », avec l'affiche de la série.
+
+## API (`server/src/index.ts`)
+
+| Méthode | Route | Rôle |
+|---|---|---|
+| GET | `/api/static-parties` | liste, avec le nombre de manqués de l'utilisateur et la séance en cours |
+| POST | `/api/static-parties` | `{sourceId, name?}` : série, saison, épisode (sa série) ou playlist |
+| GET | `/api/static-parties/:id` | détail : items + état groupe / utilisateur, membres, `missedItemIds` |
+| POST | `/:id/join`, `/:id/leave` | devenir membre / quitter |
+| DELETE | `/:id` | supprimer (créateur uniquement) |
+| POST | `/:id/session` | lancer la séance du groupe, ou rejoindre celle en cours, puis renvoyer `{partyId}` |
+| POST | `/:id/items/:itemId/watched` | marquer comme vu |
+| POST | `/:id/catch-up` | `{itemIds, mode: 'solo'\|'party'}`, renvoie `{partyId}` |
+
+## Persistance
+
+- `StaticPartyStore` écrit **un fichier JSON par watch party** :
+  `${DATA_DIR}/static-parties/<id>.json`, au format `{version: 1, party}`.
+  - `DATA_DIR` vaut `./data` par défaut, et `/data` dans l'image Docker.
+    `docker-compose.yml` y monte `./data`.
+  - Un fichier par party limite les dégâts : une écriture ne touche que la
+    party modifiée, et un fichier corrompu ne coûte que cette party-là.
+  - L'écriture est atomique (`.tmp` puis `rename`) et debouncée (2 s) party
+    par party. Elle est flushée de façon synchrone sur `SIGTERM`/`SIGINT`.
+  - Au démarrage, un `.tmp` restant (écriture interrompue) est supprimé ; le
+    vrai fichier, s'il existe, est la dernière version complète.
+  - Un fichier corrompu (ou dont le nom ne correspond pas à l'id) est
+    renommé en `.corrupt` et ignoré ; les autres parties se chargent
+    normalement. Le serveur ne crashe jamais pour ça.
+  - Supprimer une party supprime son fichier et annule toute sauvegarde en
+    attente pour elle.
+  - Migration : l'ancien fichier unique `${DATA_DIR}/static-parties.json` de
+    la première version est éclaté en un fichier par party au premier
+    démarrage, puis renommé en `.migrated` (conservé, pas supprimé).
+- Pas de SQLite : l'image tourne en Node 20 (pas de `node:sqlite`), une
+  dépendance native serait une première dans l'image, et les données sont
+  minuscules.
+- `livePartyId` n'est jamais persisté : un redémarrage termine toutes les
+  séances, et la reprise se fait depuis la position enregistrée.
+
+## Client
+
+- `views/staticParty/` (route `/static/:id`) contient :
+  - l'en-tête, avec la progression du groupe et le bouton lancer / rejoindre
+    la séance ;
+  - « Tu as manqué », avec pour chaque élément cases à cocher, *Regarder en
+    solo* et *Marquer comme vu*, plus deux actions groupées : rattraper en
+    solo, ou lancer une watch party de rattrapage ;
+  - les membres ;
+  - la liste complète des items.
+- Page série (`views/series`) :
+  - en-tête : « Lancer toute la série » (watch party) et « Créer une lounge
+    party » (série entière) ;
+  - au-dessus des épisodes de l'onglet de saison sélectionné : « Lancer
+    cette saison » (watch party) et « Lounge party de cette saison ».
+- « Créer une lounge party » sur `views/playlist` (vidéo uniquement).
+- Onglet dédié « Lounge parties » (sidebar et menu mobile), route
+  `/static` (`views/staticParties/`) : une carte par watch party avec la
+  progression, le prochain élément, un badge « N manqués » et une pastille
+  « séance en cours ». L'onglet reste actif sur la page d'une party.
+- Séparation avec les watch/listen parties classiques : la liste « Parties
+  en cours » de l'accueil exclut les séances de lounge party
+  (`staticPartyId` non nul) ; elles ne s'affichent que dans leur onglet.
+
+## Limites connues
+
+- « Vu » reste une heuristique : passer à la suite compte comme vu, comme
+  pour le flag `Played` d'Emby. Il n'y a pas de seuil de pourcentage.
+- La liste et le détail relisent la source Emby à chaque affichage (une
+  requête par watch party pour la liste). C'est acceptable à l'échelle d'un
+  serveur perso ; à mettre en cache si la liste grossit.
+- Plusieurs watch parties statiques peuvent exister sur la même série
+  (des groupes différents) : c'est voulu, sans déduplication.