feat: track info drawer (Get Info-style)

Add a right-side track info drawer that sits to the right of the queue
panel when both are open. Shows a large cover, title/artist/album links,
a Play/Queue/Edit actions row, and Status/General/File/Identifiers
sections (empty rows omitted). Opens from the track context menu, the
player now-playing tile, and the queue now-playing card.

- ui slice: trackInfoId + open/closeTrackInfo
- TrackInfoDrawer rendered after QueuePanel in AppShell; overlays content
  on narrow viewports
- map source/createdAt/enrichedAt from the wire (were unmapped)
- formatDateTime helper, info icon, i18n (en/ru)
- drop orphaned toggleNowPlaying/isNowPlayingOpen from player slice

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/api/types.ts

@@ -30,6 +30,12 @@ export interface Track {
   format?: string;
   bitrate?: number;
   liked: boolean;
+  /** Where the track entered the library (e.g. `upload`, `local_folder`). */
+  source?: string;
+  /** ISO timestamp the track was added to the library. */
+  createdAt?: string;
+  /** ISO timestamp the last successful enrichment ran; undefined if never. */
+  enrichedAt?: string;
 }
 
 export interface Album {