feat(plex): adaptive (faceted) filters — each filter narrows the others

The sidebar's filter chips/bounds now ADAPT to the active filters: /facets takes the
current filters and computes each group's available values with all the OTHER active
filters applied but not its own (standard faceted search). So picking e.g. IMDb rating
>=8 trims the genre/content-rating chips + year bounds to what's still reachable, and
picking a genre narrows them further — while a multi-select group (genres) still shows
options to add. Extracted _meta_filter_conds (shared by browse/unified/facets), and the
frontend passes the live filters to plexFacets (query keyed on them, previous chips kept
during refetch). Search text is intentionally not factored into facets.

frontend/src/components/PlexSidebar.tsx

@@ -62,11 +62,13 @@ export default function PlexSidebar({
     qc.invalidateQueries({ queryKey: ["plex-playlists"] });
     onOpenPlaylist(pl.id);
   }
-  // Facet values (genres/ratings/bounds) for the current cross-library scope (movie|show|both).
+  // 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.
   const facetsQ = useQuery({
-    queryKey: ["plex-facets", scope],
-    queryFn: () => api.plexFacets(scope),
+    queryKey: ["plex-facets", scope, filters],
+    queryFn: () => api.plexFacets(scope, filters),
     enabled: !!scope,
+    placeholderData: (prev) => prev, // keep the old chips visible during the refetch (no flicker)
   });
   const facets = facetsQ.data;
 

frontend/src/lib/api.ts

@@ -1210,8 +1210,26 @@ export const api = {
     }
     return req(`/api/plex/library?${u.toString()}`);
   },
-  plexFacets: (scope: string): Promise<PlexFacets> =>
-    req(`/api/plex/facets?scope=${encodeURIComponent(scope)}`),
+  // Facets ADAPT to the active filters (faceted search) — pass them so each group narrows the others.
+  plexFacets: (scope: string, f?: PlexFilters): Promise<PlexFacets> => {
+    const u = new URLSearchParams({ scope });
+    if (f) {
+      if (f.genres?.length) u.set("genres", f.genres.join(","));
+      if (f.genreMode === "all") u.set("genre_mode", "all");
+      if (f.contentRatings?.length) u.set("content_ratings", f.contentRatings.join(","));
+      if (f.yearMin != null) u.set("year_min", String(f.yearMin));
+      if (f.yearMax != null) u.set("year_max", String(f.yearMax));
+      if (f.ratingMin != null) u.set("rating_min", String(f.ratingMin));
+      if (f.durationMin != null) u.set("duration_min", String(f.durationMin));
+      if (f.durationMax != null) u.set("duration_max", String(f.durationMax));
+      if (f.addedWithin) u.set("added_within", f.addedWithin);
+      if (f.directors?.length) u.set("directors", f.directors.join(","));
+      if (f.actors?.length) u.set("actors", f.actors.join(","));
+      if (f.studios?.length) u.set("studios", f.studios.join(","));
+      if (f.collection) u.set("collection", f.collection);
+    }
+    return req(`/api/plex/facets?${u.toString()}`);
+  },
   plexPeople: (library: string, q: string): Promise<{ people: PlexPerson[] }> =>
     req(`/api/plex/people?library=${encodeURIComponent(library)}&q=${encodeURIComponent(q)}`),
   plexCollections: (library: string, q?: string): Promise<{ collections: PlexCollection[] }> =>