fix(plex): address code-review findings (F1-F3, F5, F9)

- F1: refresh grid after playback/collection-edit — invalidate the renamed
  ["plex-library"] query key in PlexPlayer + PlexCollectionEditor (was stale
  ["plex-browse"], a dead no-op)
- F2: exclude hidden movies from facet counts/bounds — the movie facet base now
  always joins watch-state and mirrors unified_library's status branches, so
  facets match the visible grid exactly
- F3: show_detail/item_detail live-Plex enrichment degrades instead of 500ing —
  broaden the best-effort block to except Exception
- F5: don't re-run the heavy facet computation on sort-direction toggles — key
  the facets query only on fields plexFacets actually sends
- F9: optimistic watched-toggle also updates the search Episodes section and
  gives toggleEpisodeWatched an optimistic path (shared optimisticStatus helper)

frontend/src/components/PlexBrowse.tsx

@@ -188,26 +188,33 @@ export default function PlexBrowse({
     infoScrollRef.current = 0; // fresh info page starts at the top
     sub.open({ kind: "info", id: card.id });
   }
-  async function toggleWatched(card: PlexCard) {
-    const next = card.status === "watched" ? "new" : "watched";
-    // Optimistically flip the card in every cached library page so the quick toggle reacts instantly
-    // and reliably BOTH ways (mark and un-mark), then reconcile with the server.
+  // Optimistically flip a card's status in every cached library page — both the title grid (`items`)
+  // and the search "Episodes" section (`episodes`) — so the quick toggle reacts instantly and reliably
+  // BOTH ways (mark and un-mark). An id matches in only one array, so touching both is safe.
+  function optimisticStatus(id: string, next: string) {
     qc.setQueriesData<InfiniteData<PlexUnifiedResult>>({ queryKey: ["plex-library"] }, (old) =>
       old
         ? {
             ...old,
             pages: old.pages.map((pg) => ({
               ...pg,
-              items: pg.items.map((it) => (it.id === card.id ? { ...it, status: next } : it)),
+              items: pg.items.map((it) => (it.id === id ? { ...it, status: next } : it)),
+              episodes: pg.episodes.map((ep) => (ep.id === id ? { ...ep, status: next } : ep)),
             })),
           }
         : old,
     );
+  }
+  async function toggleWatched(card: PlexCard) {
+    const next = card.status === "watched" ? "new" : "watched";
+    optimisticStatus(card.id, next);
     await api.plexSetState(card.id, next).catch(() => {});
     qc.invalidateQueries({ queryKey: ["plex-library"] });
   }
   async function toggleEpisodeWatched(ep: PlexCard) {
-    await api.plexSetState(ep.id, ep.status === "watched" ? "new" : "watched").catch(() => {});
+    const next = ep.status === "watched" ? "new" : "watched";
+    optimisticStatus(ep.id, next);
+    await api.plexSetState(ep.id, next).catch(() => {});
     qc.invalidateQueries({ queryKey: ["plex-library"] });
   }
   // Apply a metadata filter (clicked on an info page / show hero / cast) then show the unified grid.

frontend/src/components/PlexCollectionEditor.tsx

@@ -50,7 +50,7 @@ export default function PlexCollectionEditor({
   const refresh = () => {
     qc.invalidateQueries({ queryKey: ["plex-collections"] });
     qc.invalidateQueries({ queryKey: ["plex-item", item.id] });
-    qc.invalidateQueries({ queryKey: ["plex-browse"] });
+    qc.invalidateQueries({ queryKey: ["plex-library"] });
     onChanged();
   };
 

frontend/src/components/PlexPlayer.tsx

@@ -489,7 +489,7 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
           old ? { ...old, position_seconds: pos } : old,
         );
       }
-      qc.invalidateQueries({ queryKey: ["plex-browse"] });
+      qc.invalidateQueries({ queryKey: ["plex-library"] });
       qc.invalidateQueries({ queryKey: ["plex-show"] });
     };
   }, [id, qc]);

frontend/src/components/PlexSidebar.tsx

@@ -64,8 +64,12 @@ export default function PlexSidebar({
   }
   // Facet values (genres/ratings/bounds) for the current scope, ADAPTED to the active filters
   // (faceted search) — so picking one filter narrows what the others offer. Refetches on any change.
+  // Key only on the fields plexFacets actually sends — sortDir/collectionTitle don't reach /facets,
+  // so keying on the whole `filters` object would re-run the heavy facet computation on every
+  // sort-direction toggle (or chip-title change) for an identical request.
+  const { sortDir: _sd, collectionTitle: _ct, ...facetKey } = filters;
   const facetsQ = useQuery({
-    queryKey: ["plex-facets", scope, show, filters],
+    queryKey: ["plex-facets", scope, show, facetKey],
     queryFn: () => api.plexFacets(scope, filters, show),
     enabled: !!scope,
     placeholderData: (prev) => prev, // keep the old chips visible during the refetch (no flicker)