music: dismiss the dock when playback ends

The in-flow music dock reserves its height whenever a track is loaded (current),
even paused — so after a queue finished (onEndOfQueue set playing=false but kept
the queue) the dock lingered, shifting the layout up with a faint idle bar. On
natural end-of-queue, close() the queue so the dock releases its space. The saved
now-playing snapshot is untouched, so reload still resumes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/workspaces/officerdev/src/MusicPlayer/MusicPlayerHost.tsx

@@ -67,6 +67,8 @@ export const MusicPlayerHost = () => {
   syncIndexRef.current = syncIndex;
   const setPlayingRef = useRef(setPlaying);
   setPlayingRef.current = setPlaying;
+  const closeRef = useRef(close);
+  closeRef.current = close;
 
   const withToken = (u: string) => (token ? `${u}${u.includes('?') ? '&' : '?'}token=${encodeURIComponent(token)}` : u);
   const streamUrl = (t: PlayerTrack) =>
@@ -101,7 +103,9 @@ export const MusicPlayerHost = () => {
         engineIndexRef.current = i; // engine advanced on its own → mirror to UI without restarting
         syncIndexRef.current(i);
       },
-      onEndOfQueue: () => setPlayingRef.current(false),
+      // Queue finished on its own → clear it so the in-flow dock releases its space (no idle bar lingering
+      // after playback). The saved snapshot is left intact, so a reload still resumes where you left off.
+      onEndOfQueue: () => closeRef.current(),
       onLoadingChange: setLoading,
     });
     engineRef.current = engine;