Fix play behaviour in track view

- Version switching now stops playback and resets UI state
- Playback must be started manually after version switch
- Added space key shortcut for play/pause toggle
- UI elements correctly reflect playback state

Fixes: Play/pause controls work correctly after version switching
Improves: User experience with keyboard shortcuts

web/src/hooks/useWaveform.ts

@@ -39,10 +39,9 @@ export function useWaveform(
     ws.on("ready", () => {
       setIsReady(true);
       options.onReady?.(ws.getDuration());
-      // Auto-play if previous version was playing
-      if (wasPlayingRef.current) {
-        ws.play();
-      }
+      // Reset playing state when switching versions
+      setIsPlaying(false);
+      wasPlayingRef.current = false;
     });
 
     ws.on("audioprocess", (time) => {