feat: remove album from song subtitle; add Go to Album in context menu

Album name no longer shown inline next to the artist — navigate via
right-click > Zum Album instead, available everywhere.

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

src/ui.js

@@ -135,6 +135,7 @@ export function showCtxMenu(e, song, list, idx) {
           .catch(err => toast('Fehler: ' + err.message));
     }},
     { sep: true },
+    { icon: '💿', label: 'Zum Album', fn: () => song.albumId && navigate('album-detail', { id: song.albumId, name: song.album||'', artist: song.artist||'', artistId: song.artistId||'', coverArt: song.coverArt||'' }) },
     { icon: 'ℹ', label: 'Song-Info', fn: () => showSongInfo(song) },
     { icon: '⬇', label: 'Herunterladen', fn: () => dlSongLocal(song) },
   ];