⬆️ version to v0.3.41 — async queue sync refactoring

- Add `SyncCancelled` error variant for non-fatal cancellations
- Refactor queue sync to async via `MusicQueue::schedule_sync()`
  - Extract browse+conversion into internal helper
- Update all `QueueBackend::sync_queue()` signatures to accept cancel token and on_ready callback  
- Implement early-start logic (on pivot preservation or first insert)
 - Add `QueueReadyToPlay` and  ‘ QueueSyncCancelled➔ SSE events
- Replace blocking `refresh_attached_queue_for()` with non-blocking async dispatch in control_point.rs  
- Bump version to v0.3.41

version.txt

@@ -1 +1 @@
-0.3.40
+0.3.41