Give static watch parties their own tab and one file per party

- new "Parties permanentes" tab (/static, sidebar + mobile sheet), highlighted on a party's own page too; the home page no longer lists static parties, and its live "Watch parties en cours" list leaves their sessions out - StaticPartyStore now writes data/static-parties/<id>.json - one file per party, debounced per party, so a write only touches the party that changed and a corrupt file only costs that party (moved aside to .corrupt, the rest still load); leftover .tmp files are cleaned up; deleting a party removes its file and cancels any pending save - the first release's single static-parties.json is migrated once on load, then kept as .migrated Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-24 19:16:55 +02:00 · 2026-09-24 19:16:55 +02:00 · 1e437e4a91
commit 1e437e4a91
parent 2de375ac62
15 changed files with 519 additions and 224 deletions
--- a/client/src/app.ts
+++ b/client/src/app.ts
@ -11,6 +11,7 @@ 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);
@ -21,6 +22,7 @@ route('/artist/:id', renderArtist);
 route('/album/:id', renderAlbum);
 route('/playlist/:id', renderPlaylist);
 route('/party/:id', renderPartyPlayer);
+route('/static', renderStaticParties);
 route('/static/:id', renderStaticParty);

 /**
--- a/client/src/shell/Shell.html
+++ b/client/src/shell/Shell.html
@ -3,6 +3,7 @@
    <div class="sidebarBrand">Watch Party</div>
    <nav class="sidebarNav" id="sidebarNav">
      <a href="#/home" class="navItem">Accueil</a>
+      <a href="#/static" class="navItem">Parties permanentes</a>
      <div class="navSectionLabel">Bibliothèques</div>
      <p class="hint" id="libStatus"><span class="spinner"></span>Chargement...</p>
    </nav>
@ -41,6 +42,7 @@
         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>Parties permanentes</a>
    <div class="navSectionLabel">Bibliothèques</div>
    <div class="sheetGrid" id="mobileLibGrid"></div>
    <div id="mobilePlaylistsSlot"></div>
--- a/client/src/shell/Shell.ts
+++ b/client/src/shell/Shell.ts
@ -18,6 +18,8 @@ const SHOWS_ICON_SVG = '<svg viewBox="0 0 24 24"><rect x="3" y="5.5" width="18"
 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 "Watch parties permanentes" tab - 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
@ -53,6 +55,7 @@ export async function renderShell(appEl: HTMLElement): Promise<HTMLElement> {
  appEl.innerHTML = html;

  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.
@ -98,8 +101,11 @@ export async function renderShell(appEl: HTMLElement): Promise<HTMLElement> {

  const highlight = () => {
    appEl.querySelectorAll('.navItem').forEach((a) => {
-      const isHome = a.getAttribute('href') === '#/home';
-      a.classList.toggle('active', a.getAttribute('href') === location.hash || (isHome && !location.hash));
+      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();
--- a/client/src/views/home/Home.css
+++ b/client/src/views/home/Home.css
@ -60,41 +60,3 @@
  color: var(--accent-bright);
  font-weight: 600;
 }
-
-/* ---- Static (persistent) watch parties ----
-   A whole card is the link (to /static/:id) - reuses .partyCard's layout,
-   minus the default anchor styling. */
-.staticCard {
-  color: inherit;
-  text-decoration: none;
-}
-
-.staticCard:hover { background: #2b252e; }
-
-.staticCardLive {
-  color: var(--accent-bright);
-  font-size: 12px;
-  font-weight: 600;
-}
-
-.staticCardMissed {
-  flex-shrink: 0;
-  padding: 4px 10px;
-  border-radius: 12px;
-  background: var(--danger);
-  color: #fff;
-  font-size: 12px;
-  font-weight: 600;
-}
-
-/* A live session's link back to the static watch party it belongs to. */
-.partyCardStatic {
-  color: var(--accent-bright);
-  font-size: 12px;
-  text-decoration: none;
-  white-space: nowrap;
-  overflow: hidden;
-  text-overflow: ellipsis;
-}
-
-.partyCardStatic:hover { text-decoration: underline; }
--- a/client/src/views/home/Home.html
+++ b/client/src/views/home/Home.html
@ -7,9 +7,4 @@
  <div id="partiesCarousel" class="carousel"></div>
 </section>

-<section class="section" id="staticSection" hidden>
-  <h2>Watch parties permanentes</h2>
-  <div id="staticCarousel" class="carousel"></div>
-</section>
-
 <div id="recentSections"></div>
--- a/client/src/views/home/Home.ts
+++ b/client/src/views/home/Home.ts
@ -7,8 +7,7 @@ import { navigate } from '../../router';
 import { escapeHtml, tileHtml, wireTileButtons } from '../../tiles';
 import { LOADING_HINT } from '../../loading';
 import { showToast } from '../../toast';
-import { listStaticParties } from '../../api/staticParty';
-import type { LobbyPartyDto, StaticPartySummaryDto } from '../../types';
+import type { LobbyPartyDto } from '../../types';

 export function renderHome(root: HTMLElement): () => void {
  root.innerHTML = html;
@ -19,20 +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.
-  // Static watch parties are a REST fetch (their data changes rarely), but
-  // re-fetched whenever the set of live static-party sessions in the lobby
-  // changes - a session starting/ending is what moves their cards'
-  // "en cours"/progress state. Not on every lobby snapshot: those also
-  // fire on every pause/join, and each static-party fetch reads Emby.
-  let staticSessionsKey: string | null = null;
-  const lobby = connectLobby((parties) => {
-    renderParties(root, parties);
-    const key = parties.map((p) => p.staticPartyId).filter(Boolean).sort().join(',');
-    if (key !== staticSessionsKey) {
-      staticSessionsKey = key;
-      loadStaticParties(root);
-    }
-  });
+  // 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);
@ -72,7 +60,6 @@ function renderParties(root: HTMLElement, parties: LobbyPartyDto[]): void {
      <img class="${p.mediaType === 'music' ? 'partyCardArt--square' : ''}" src="${p.itemImageUrl || ''}" alt="" onerror="this.classList.add('noImage')" />
      <div class="partyCardInfo">
        <strong>${escapeHtml(p.itemName || '')}</strong>
-        ${p.staticPartyId ? `<a class="partyCardStatic" href="#/static/${escapeHtml(p.staticPartyId)}">↻ ${escapeHtml(p.staticPartyName || '')}</a>` : ''}
        <span class="hint">
          ${escapeHtml(p.hostUserName || '')} · ${p.memberCount} participant${p.memberCount > 1 ? 's' : ''}
          · <span class="elapsed"
@ -108,39 +95,6 @@ function renderParties(root: HTMLElement, parties: LobbyPartyDto[]): void {
  updateElapsedLabels(root);
 }

-/** Fetches and renders the "Watch parties permanentes" section - hidden
- *  when there are none. A failure only hides the section: the rest of the
- *  home page doesn't depend on it. */
-function loadStaticParties(root: HTMLElement): void {
-  listStaticParties()
-    .then((parties) => renderStaticParties(root, parties))
-    .catch((err: unknown) => {
-      console.error('[home] static parties failed to load', err);
-      const section = root.querySelector('#staticSection') as HTMLElement | null;
-      if (section) section.hidden = true;
-    });
-}
-
-/** One card per static watch party: progress, the viewer's missed count,
- *  and whether a session is running right now. */
-function renderStaticParties(root: HTMLElement, parties: StaticPartySummaryDto[]): void {
-  const section = root.querySelector('#staticSection') as HTMLElement | null;
-  const list = root.querySelector('#staticCarousel');
-  if (!section || !list) return; // navigated away mid-flight
-  section.hidden = !parties.length;
-  list.innerHTML = parties.map((p) => `
-    <a class="partyCard staticCard" href="#/static/${escapeHtml(p.id)}">
-      <img src="${escapeHtml(p.imageUrl)}" alt="" onerror="this.classList.add('noImage')" />
-      <div class="partyCardInfo">
-        <strong>${escapeHtml(p.name)}</strong>
-        <span class="hint">${p.groupWatchedCount}/${p.itemCount} vus · ${p.memberCount} membre${p.memberCount > 1 ? 's' : ''}</span>
-        ${p.livePartyId ? '<span class="staticCardLive">● Séance en cours</span>' : ''}
-      </div>
-      ${p.missedCount ? `<span class="staticCardMissed" title="Éléments manqués">${p.missedCount} manqué${p.missedCount > 1 ? 's' : ''}</span>` : ''}
-    </a>
-  `).join('');
-}
-
 const TICKS_PER_SECOND = 10000000; // Emby/.NET convention: 1 tick = 100ns, same as everywhere else this app touches durations/positions

 /**
--- a/client/src/views/staticParties/StaticParties.css
+++ b/client/src/views/staticParties/StaticParties.css
@ -0,0 +1,81 @@
+/* ---- "Watch parties permanentes" 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; }
+}
--- a/client/src/views/staticParties/StaticParties.html
+++ b/client/src/views/staticParties/StaticParties.html
@ -0,0 +1,9 @@
+<div class="pageHeader">
+  <h1>Watch parties permanentes</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 watch party permanente ».
+</p>
+<div class="staticGrid" id="staticGrid"></div>
--- a/client/src/views/staticParties/StaticParties.ts
+++ b/client/src/views/staticParties/StaticParties.ts
@ -0,0 +1,76 @@
+import './StaticParties.css';
+import html from './StaticParties.html';
+import { connectLobby } from '../../api/party';
+import { listStaticParties } from '../../api/staticParty';
+import { escapeHtml } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
+import type { StaticPartySummaryDto } from '../../types';
+
+/**
+ * Route `/static` - the "Watch parties permanentes" 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">${escapeHtml((err as Error).message)}</p>`;
+    });
+}
+
+/** One card per static party: progress, next item, the viewer's missed
+ *  count, and whether a session is running right now. */
+function render(grid: HTMLElement, parties: StaticPartySummaryDto[]): void {
+  if (!parties.length) {
+    grid.innerHTML = '<p class="hint">Aucune watch party permanente pour le moment.</p>';
+    return;
+  }
+  grid.innerHTML = parties.map((p) => {
+    const percent = p.itemCount ? Math.round((p.groupWatchedCount / p.itemCount) * 100) : 0;
+    return `
+      <a class="staticCard" href="#/static/${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">${p.sourceType === 'series' ? 'Série' : 'Playlist'} · ${p.groupWatchedCount}/${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('');
+}
--- a/client/src/views/staticParty/StaticParty.ts
+++ b/client/src/views/staticParty/StaticParty.ts
@ -164,7 +164,7 @@ function wireActions(root: HTMLElement, staticId: string): void {
    runBusy(deleteBtn, async () => {
      await deleteStaticParty(staticId);
      showToast('Watch party supprimée.');
-      navigate('/home');
+      navigate('/static');
    });
  });

--- a/docs/architecture.md
+++ b/docs/architecture.md
@ -4576,10 +4576,16 @@ short version:
  so the player, sync, shared stream, lobby and host handoff are all
  reused unchanged. `PartyService` calls into `StaticPartyService`,
  never the other way around.
- **This app's first on-disk state.** A JSON file
-  (`StaticPartyStore`, `DATA_DIR`) that is atomic, debounced, and
-  flushed on SIGTERM. "Party lifecycle" above still holds for ordinary
-  parties.
+- **This app's first on-disk state.** One JSON file per static party
+  (`StaticPartyStore`, `${DATA_DIR}/static-parties/<id>.json`). Writes
+  are atomic, debounced per party, and flushed on SIGTERM. It started
+  as a single file for every party; that was split, so a write only
+  touches the party that changed and a corrupt file costs only that
+  party. The old single file is migrated once, on first load. "Party
+  lifecycle" above still holds for ordinary parties.
+- **Its own tab.** "Parties permanentes" (`/static`) lists them. The
+  home page's live "Watch parties en cours" list leaves their sessions
+  out, so classic and permanent parties never share a list.
 - **"Completed" gained a second trigger.** `PartyService
  .completeCurrentItem` is now the one place an item counts as done. It
  handles Emby Played, as before, plus static progress. It runs from
--- a/server/src/services/StaticPartyService.ts
+++ b/server/src/services/StaticPartyService.ts
@ -70,7 +70,8 @@ export function mergeItemLists(existing: QueueItem[], fresh: QueueItem[]): { ite
 * PartyService (PartyService calls into this one), keeping the dependency
 * one-way.
 *
- * Persisted through StaticPartyStore after every change.
+ * Persisted through StaticPartyStore after every change - one file per
+ * party, so only the party that changed is ever rewritten.
 */
 class StaticPartyServiceClass {
  /** Every static party, by id. */
@ -118,7 +119,7 @@ class StaticPartyServiceClass {
    sp.members[creator.userId] = this.newMember(creator);
    this.partiesById.set(sp.id, sp);
    Logger.staticParty(`created id=${sp.id} name="${name}" source=${source.type}:${source.sourceId} items=${items.length} by=${Logger.who(creator.userId, creator.userName)}`);
-    this.persist();
+    this.persist(sp);
    return sp;
  }

@ -128,13 +129,13 @@ class StaticPartyServiceClass {
    if (existing) {
      existing.userName = who.userName;
      existing.lastSeenUtc = Date.now();
-      this.persist();
+      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();
+    this.persist(sp);
    return member;
  }

@ -145,7 +146,7 @@ class StaticPartyServiceClass {
    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();
+    this.persist(sp);
  }

  /** Deletes the party for good - creator only. Returns false (and does
@ -157,7 +158,7 @@ class StaticPartyServiceClass {
    }
    this.partiesById.delete(sp.id);
    Logger.staticParty(`deleted id=${sp.id} name="${sp.name}"`);
-    this.persist();
+    StaticPartyStore.remove(sp.id);
    return true;
  }

@ -169,7 +170,7 @@ class StaticPartyServiceClass {
    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();
+    if (changed) this.persist(sp);
  }

  /** What the group's next session plays: everything from the group's
@ -184,7 +185,7 @@ class StaticPartyServiceClass {
    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();
+      this.persist(sp);
    }
  }

@ -211,7 +212,7 @@ class StaticPartyServiceClass {
      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();
+    this.persist(sp);
  }

  /** The group session's current position - saved so the next session
@ -222,7 +223,7 @@ class StaticPartyServiceClass {
    if (!sp || sp.items[sp.group.nextIndex]?.itemId !== itemId) return;
    if (sp.group.resumePositionTicks === positionTicks) return;
    sp.group.resumePositionTicks = positionTicks;
-    this.persist();
+    this.persist(sp);
  }

  /** A linked live party ended - forget it as the group's live session. */
@ -231,7 +232,7 @@ class StaticPartyServiceClass {
    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();
+    this.persist(sp);
  }

  /** "Marquer comme vu" - `who` becomes a member if they weren't yet. */
@ -241,7 +242,7 @@ class StaticPartyServiceClass {
    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();
+    this.persist(sp);
    return true;
  }

@ -291,14 +292,16 @@ class StaticPartyServiceClass {
    };
  }

-  /** Writes every party to disk (debounced - see StaticPartyStore). */
-  private persist(): void {
-    StaticPartyStore.save(() => this.snapshot());
+  /** 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));
  }

-  /** Every party, minus runtime-only state. */
-  private snapshot(): PersistedStaticParty[] {
-    return Array.from(this.partiesById.values()).map(({ livePartyId: _live, ...persisted }) => persisted);
+  /** `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. */
--- a/server/src/services/StaticPartyStore.ts
+++ b/server/src/services/StaticPartyStore.ts
@ -5,121 +5,182 @@ import path from 'path';
 import { Logger } from '../Logger';
 import type { PersistedStaticParty } from '../types';

-/** The on-disk file's own shape - versioned so a future format change can
- *  migrate instead of silently misreading an older file. */
+/** 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 before writing - progress
- *  updates arrive in bursts (a whole party's members at once, the 20s
- *  position sweep), no reason to rewrite the file for each one. */
+/** 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-]+$/;
+
 /**
- * The static watch parties' persistence - one JSON file, the first and
- * only thing this app keeps on disk (everything else is deliberately
- * in-memory - see docs/architecture.md's "Party lifecycle"). A JSON file
- * rather than a database: the data is tiny (a handful of parties, a few
- * hundred item ids each), the runtime image is Node 20 (no built-in
- * `node:sqlite`), and a native SQLite binding would be the image's first
- * compiled dependency - not worth it at this size.
+ * The static watch parties' persistence: **one JSON file per party**,
+ * `${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").
 *
- * Writes are atomic (write a `.tmp` sibling, then rename over the real
- * file) so a crash mid-write never leaves a half-written file behind, and
- * debounced (SAVE_DEBOUNCE_MS). A missing file is a normal first start; an
- * unreadable/corrupt one is logged and treated as empty - the server must
- * never refuse to start over it. The corrupt file is kept aside (`.corrupt`)
- * rather than overwritten by the next save, so nothing is lost for good.
+ * 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 {
-  /** Absolute path of the JSON file - see configure(). */
-  private filePath: string | null = null;
-  /** The pending debounced save, if any. */
-  private saveTimer: NodeJS.Timeout | null = null;
-  /** What the pending save will write - always the latest snapshot. */
-  private pending: (() => PersistedStaticParty[]) | null = null;
+  /** `${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/static-parties.json`. Must be called
-   *  before load()/save() - index.ts does it at startup, tests with a
-   *  temp directory. */
+  /** 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.filePath = path.resolve(dataDir, 'static-parties.json');
+    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 file = this.requirePath();
-    let raw: string;
+    const dir = this.requireDir();
    try {
-      raw = fs.readFileSync(file, 'utf8');
+      fs.mkdirSync(dir, { recursive: true });
    } catch (err) {
-      if ((err as NodeJS.ErrnoException).code === 'ENOENT') {
-        Logger.staticParty(`no data file yet at ${file} - starting empty`);
-      } else {
-        Logger.staticParty(`could not read ${file} - starting empty: ${(err as Error).message}`);
-      }
+      Logger.staticParty(`could not create ${dir} - starting empty: ${(err as Error).message}`);
      return [];
    }
+    this.migrateLegacyFile();
+
+    let names: string[];
    try {
-      const parsed = JSON.parse(raw) as Partial<StaticPartyFile>;
-      if (!parsed || !Array.isArray(parsed.parties)) throw new Error('missing "parties" array');
-      Logger.staticParty(`loaded ${parsed.parties.length} static party(ies) from ${file}`);
-      return parsed.parties;
+      names = fs.readdirSync(dir);
    } catch (err) {
-      Logger.staticParty(`corrupt data file ${file} - moved aside to .corrupt, starting empty: ${(err as Error).message}`);
-      try {
-        fs.renameSync(file, `${file}.corrupt`);
-      } catch (renameErr) {
-        Logger.staticParty(`could not move corrupt file aside: ${(renameErr as Error).message}`);
-      }
+      Logger.staticParty(`could not list ${dir} - starting empty: ${(err as Error).message}`);
      return [];
    }
-  }

-  /** Schedules a debounced write of whatever `snapshot` returns at write
-   *  time (so a burst of changes only ever writes the final state). */
-  public save(snapshot: () => PersistedStaticParty[]): void {
-    this.pending = snapshot;
-    if (this.saveTimer) return;
-    this.saveTimer = setTimeout(() => {
-      this.saveTimer = null;
-      this.writeNow().catch((err: unknown) => {
-        Logger.staticParty(`save failed: ${(err as Error).message}`);
+    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);
-    this.saveTimer.unref(); // a pending save must never keep a test process (or a shutdown) alive
+    timer.unref(); // a pending save must never keep a test process (or a shutdown) alive
+    this.timers.set(id, timer);
  }

-  /** Writes any 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 {
-    if (this.saveTimer) {
-      clearTimeout(this.saveTimer);
-      this.saveTimer = null;
+  /** 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}: ${(err as Error).message}`);
      }
-    if (!this.pending) return;
-    const file = this.requirePath();
-    const snapshot = this.pending;
-    this.pending = null;
+    }
+  }
+
+  /** Writes every pending save immediately and synchronously - for a
+   *  graceful shutdown (SIGTERM/SIGINT), where an async write could be cut
+   *  short by the process exiting. */
+  public flushSync(): void {
+    for (const timer of this.timers.values()) clearTimeout(timer);
+    this.timers.clear();
+    const pending = Array.from(this.pending.entries());
+    this.pending.clear();
+    for (const [id, snapshot] of pending) {
+      const file = this.fileFor(id);
      try {
        fs.mkdirSync(path.dirname(file), { recursive: true });
        fs.writeFileSync(`${file}.tmp`, this.serialize(snapshot()), 'utf8');
        fs.renameSync(`${file}.tmp`, file);
-      Logger.staticParty(`flushed to ${file}`);
      } catch (err) {
-      Logger.staticParty(`flush failed: ${(err as Error).message}`);
+        Logger.staticParty(`flush failed id=${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 the pending snapshot now - atomically, via a `.tmp` rename. */
-  public async writeNow(): Promise<void> {
-    if (!this.pending) return;
-    const file = this.requirePath();
-    const snapshot = this.pending;
-    this.pending = null;
+  /** 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');
@ -130,16 +191,81 @@ class StaticPartyStoreClass {
    }
  }

-  /** The file's JSON text for `parties`. */
-  private serialize(parties: PersistedStaticParty[]): string {
-    const data: StaticPartyFile = { version: 1, parties };
+  /** 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);
  }

-  /** The configured file path - throws if configure() was never called. */
-  private requirePath(): string {
-    if (!this.filePath) throw new Error('StaticPartyStore.configure() was never called');
-    return this.filePath;
+  /** 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;
  }
 }

--- a/server/test/staticPartyService.test.ts
+++ b/server/test/staticPartyService.test.ts
@ -22,10 +22,12 @@ before(() => {
  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(path.join(dataDir, 'static-parties.json'), { force: true });
-  fs.rmSync(path.join(dataDir, 'static-parties.json.corrupt'), { force: true });
+  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();
 });

@ -166,31 +168,90 @@ describe('StaticPartyService', () => {
 });

 describe('StaticPartyStore', () => {
-  it('round-trips every party through the JSON file, without runtime-only state', async () => {
+  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();

-    const onDisk = JSON.parse(fs.readFileSync(path.join(dataDir, 'static-parties.json'), 'utf8'));
+    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.parties[0], false);
+    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 corrupt file is moved aside and the service starts empty instead of crashing', () => {
-    fs.writeFileSync(path.join(dataDir, 'static-parties.json'), '{ not json', 'utf8');
+  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(), `${other.id}.json`);
+    const past = new Date(Date.now() - 60000);
+    fs.utimesSync(otherFile, past, past);
+
+    StaticPartyService.markWatched(sp, alice, 'e1');
+    await StaticPartyStore.writeNow();
+
+    assert.equal(fs.statSync(otherFile).mtimeMs, past.getTime(), 'the untouched party\'s file was not rewritten');
+  });
+
+  it('deleting a party removes its file, even with a save still pending', async () => {
+    const sp = StaticPartyService.create(alice, { type: 'series', sourceId: 's1' }, 'A', '/img/s1', ITEMS);
+    await StaticPartyStore.writeNow();
+    StaticPartyService.markWatched(sp, alice, 'e1'); // schedules a save...
+    StaticPartyService.delete(sp, alice.userId); // ...that must not recreate the file
+    await StaticPartyStore.writeNow();
+    assert.equal(fs.existsSync(path.join(partiesDir(), `${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.equal(StaticPartyService.list().length, 0);
-    assert.ok(fs.existsSync(path.join(dataDir, 'static-parties.json.corrupt')));
+
+    assert.deepEqual(StaticPartyService.list().map((p) => p.id), [good.id]);
+    assert.ok(fs.existsSync(path.join(partiesDir(), 'broken-id.json.corrupt')));
  });

-  it('a missing file is a normal first start', () => {
+  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);
  });
--- a/spec/static-watch-party.md
+++ b/spec/static-watch-party.md
@ -85,14 +85,24 @@ des watch parties en cours.

 ## Persistance

- `StaticPartyStore` écrit un fichier JSON unique :
-  `${DATA_DIR}/static-parties.json`.
+- `StaticPartyStore` écrit **un fichier JSON par watch party** :
+  `${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`.
-  - L'écriture est atomique (`.tmp` puis `rename`) et debouncée (2 s).
-    Elle est flushée de façon synchrone sur `SIGTERM`/`SIGINT`.
-  - Un fichier corrompu est renommé en `.corrupt` et le serveur démarre à
-    vide ; il ne crashe jamais pour ça.
+  - 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.
@ -111,11 +121,13 @@ des watch parties en cours.
  - la liste complète des items.
 - Bouton « Créer une watch party permanente » sur `views/series` et sur
  `views/playlist` (vidéo uniquement).
- Accueil :
-  - une section « Watch parties permanentes », avec la progression, un badge
-    « N manqués » et une pastille « séance en cours » ;
-  - les séances live affichent un lien `↻ nom` vers leur watch party
-    statique.
+- Onglet dédié « Parties permanentes » (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 parties classiques : la liste « Watch parties en
+  cours » de l'accueil exclut les séances de watch party permanente
+  (`staticPartyId` non nul) ; elles ne s'affichent que dans leur onglet.

 ## Limites connues