Music: Featured tab with a random artist and album, from the whole library or chosen playlists

- Featured is the first Music tab; picks stay for the day on a device, Pick again rolls new ones
- Based on: choose the playlists they come from (synced across devices)
- Play mix shuffles the artist's songs; Play plays the album

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

public/style.css

@@ -976,3 +976,11 @@ body.vizopen { overflow: hidden; }
 /* Store */
 #stbody .wrap { padding: 0; max-width: none; }
 #stbody .vimg img { width: 100%; height: 100%; object-fit: cover; }
+
+/* Music: featured artist and album */
+.featgrid { display: grid; grid-template-columns: 1fr; gap: 16px; }
+@media (min-width: 760px) { .featgrid { grid-template-columns: 1fr 1fr; } }
+.featcard { display: flex; gap: 16px; align-items: center; background: var(--panel); border: 1px solid var(--line); border-radius: 16px; padding: 14px; }
+.featcard .art { width: 150px; height: 150px; border-radius: 12px; object-fit: cover; flex: none; display: block; } .featcard .art.round { border-radius: 50%; }
+.featinfo { min-width: 0; } .featinfo h2 { margin: 2px 0 0; font-size: 22px; text-transform: none; letter-spacing: 0; color: var(--text); overflow-wrap: anywhere; }
+@media (max-width: 420px) { .featcard { flex-direction: column; align-items: flex-start; } .featcard .art { width: 100%; height: auto; aspect-ratio: 1 / 1; } }