fix(pr-review): address review findings for music folder filter

- Sidebar.tsx: title={} → data-tooltip + data-tooltip-pos="right" on
  scope subtitle (CLAUDE.md rule: never use native title= for tooltips)

- authStore.ts: merge two set() calls in setMusicFolders into one atomic
  update — avoids double render on folder list arrival

- locales (all 7): remove dead libraryScopeHint key (defined but never
  rendered in any component)

- Genres.tsx: remove musicLibraryFilterVersion from effect deps —
  getGenres is intentionally not folder-scoped, re-fetching on filter
  change was a no-op waste

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/Genres.tsx

@@ -49,7 +49,6 @@ const SCROLL_KEY = 'genres-scroll';
 export default function Genres() {
   const { t } = useTranslation();
   const navigate = useNavigate();
-  const musicLibraryFilterVersion = useAuthStore(s => s.musicLibraryFilterVersion);
   const [genres, setGenres] = useState<SubsonicGenre[]>([]);
   const [loading, setLoading] = useState(true);
   const containerRef = useRef<HTMLDivElement>(null);
@@ -61,7 +60,7 @@ export default function Genres() {
         setGenres(sorted);
       })
       .finally(() => setLoading(false));
-  }, [musicLibraryFilterVersion]);
+  }, []); // getGenres is not folder-scoped — no dep on musicLibraryFilterVersion
 
   // Restore scroll position after genres are rendered
   useEffect(() => {