fix: 15s scrobble, play count clarity, star always visible, all-songs actions

- Scrobble timer: 12s → 15s
- Play count moved after action buttons, shown as "23×" (distinct from duration)
- Song star/menu buttons always visible (removed opacity:0 hover-only rule)
- Artist all-songs page: added star + 3-dots to every row (same as top songs)
- Hero card: picks from full recent+frequent pool (was capped at first 5 = all frequent)

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

src/player.js

@@ -27,7 +27,7 @@ function _scheduleScrobble(id) {
   _scrobbleTimer = setTimeout(() => {
     if (_scrobbleId) api('scrobble', `&id=${_scrobbleId}&time=${Date.now()}`).catch(() => {});
     _scrobbleId = null;
-  }, 12_000);
+  }, 15_000);
 }
 function _cancelScrobble() {
   clearTimeout(_scrobbleTimer);