feat(device-sync): show album artist in both panels

Adds optional artist field to DeviceSyncSource and renders it inline
next to the album name ("Album · Artist") in the on-device list.
BrowserRow (left panel) uses the same inline format so albums in search,
random picks and under expanded artists all read consistently. Playlists
unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/store/deviceSyncStore.ts

@@ -5,6 +5,8 @@ export interface DeviceSyncSource {
   type: 'album' | 'playlist' | 'artist';
   id: string;
   name: string;
+  /** Album artist — only set when type === 'album'. Shown as a subtitle in the device list. */
+  artist?: string;
 }
 
 interface DeviceSyncState {