feat(ratings): mix cutoff filter for random flows and home, i18n

Apply the same per-axis star cutoff to random mix (multi-batch fetch until
full), random albums, Hero, and Home hero/discover rows. Prefetch artist and
album ratings via Subsonic when list payloads omit them. Exclude items when
0 < rating ≤ threshold; 0 or missing counts as unrated.

Settings: rating filter description interpolates sidebar menu labels; Russian
strings for custom title bar; short axis labels aligned across locales.

src/api/subsonic.ts

@@ -68,6 +68,13 @@ export interface SubsonicAlbum {
   userRating?: number;
 }
 
+/** OpenSubsonic `artists` / `albumArtists` entries on a child song (may include `userRating`). */
+export interface SubsonicOpenArtistRef {
+  id?: string;
+  name?: string;
+  userRating?: number;
+}
+
 export interface SubsonicSong {
   id: string;
   title: string;
@@ -84,6 +91,8 @@ export interface SubsonicSong {
   /** Some OpenSubsonic responses attach parent ratings on child songs. */
   albumUserRating?: number;
   artistUserRating?: number;
+  artists?: SubsonicOpenArtistRef[];
+  albumArtists?: SubsonicOpenArtistRef[];
   // Audio technical info
   bitRate?: number;
   suffix?: string;
@@ -260,6 +269,71 @@ export async function getAlbum(id: string): Promise<{ album: SubsonicAlbum; song
   return { album, songs: song ?? [] };
 }
 
+const MIX_RATING_PREFETCH_CONCURRENCY = 8;
+
+function parseEntityUserRating(v: unknown): number | undefined {
+  if (v === null || v === undefined) return undefined;
+  const n = typeof v === 'number' ? v : Number(v);
+  if (!Number.isFinite(n)) return undefined;
+  return n;
+}
+
+/** Parallel `getArtist` calls to fill mix/album filters when list endpoints omit ratings. */
+export async function prefetchArtistUserRatings(
+  ids: string[],
+  concurrency = MIX_RATING_PREFETCH_CONCURRENCY,
+): Promise<Map<string, number>> {
+  const unique = [...new Set(ids.filter(Boolean))];
+  const out = new Map<string, number>();
+  if (!unique.length) return out;
+  let next = 0;
+  async function worker() {
+    for (;;) {
+      const i = next++;
+      if (i >= unique.length) return;
+      const id = unique[i];
+      try {
+        const { artist } = await getArtist(id);
+        const r = parseEntityUserRating(artist.userRating);
+        if (r !== undefined) out.set(id, r);
+      } catch {
+        /* ignore */
+      }
+    }
+  }
+  const nWorkers = Math.min(concurrency, unique.length);
+  await Promise.all(Array.from({ length: nWorkers }, () => worker()));
+  return out;
+}
+
+/** Parallel `getAlbum` calls when `albumList2` entries lack `userRating`. */
+export async function prefetchAlbumUserRatings(
+  ids: string[],
+  concurrency = MIX_RATING_PREFETCH_CONCURRENCY,
+): Promise<Map<string, number>> {
+  const unique = [...new Set(ids.filter(Boolean))];
+  const out = new Map<string, number>();
+  if (!unique.length) return out;
+  let next = 0;
+  async function worker() {
+    for (;;) {
+      const i = next++;
+      if (i >= unique.length) return;
+      const id = unique[i];
+      try {
+        const { album } = await getAlbum(id);
+        const r = parseEntityUserRating(album.userRating);
+        if (r !== undefined) out.set(id, r);
+      } catch {
+        /* ignore */
+      }
+    }
+  }
+  const nWorkers = Math.min(concurrency, unique.length);
+  await Promise.all(Array.from({ length: nWorkers }, () => worker()));
+  return out;
+}
+
 export async function getArtists(): Promise<SubsonicArtist[]> {
   const data = await api<{ artists: { index: Array<{ artist: SubsonicArtist[] }> } }>('getArtists.view', {
     ...libraryFilterParams(),