feat(track): show now-playing bars overlay on cover art

Overlay the accent-coloured "hopping bars" PlayingIndicator on a
track's cover art wherever TrackRow appears when it's the active
player track, and reuse the same component/overlay for the current
entry's cover in the queue panel.

src/components/player/QueuePanel.tsx

@@ -248,7 +248,14 @@ function QueueRow({
           <Icon name="dots-six-vertical" />
         </span>
       )}
-      <ArtTile seed={albumTitle} size={36} label={albumTitle} src={artUrl} />
+      <div className="qart">
+        <ArtTile seed={albumTitle} size={36} label={albumTitle} src={artUrl} />
+        {isCurrent && (
+          <div className="cover-playing">
+            <PlayingIndicator animate={isPlaying} />
+          </div>
+        )}
+      </div>
       <div className="qt">
         <div className="t">{resolved?.title ?? entry.title}</div>
         <div className="r">{resolved?.artistName ?? entry.artistName}</div>