refactor(nbstore): improve doc state management (#12359)

Move the `waitForSynced` method from `frontend` to `nbstore worker` to make the wait more reliable

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Added explicit tracking of document updating state to indicate when data is being applied or saved.
  - Introduced new methods to wait for update and synchronization completion with abort support.

- **Improvements**
  - Applied throttling with leading and trailing emissions to state observables for smoother UI updates.
  - Refined synchronization waiting logic for clearer separation between update completion and sync completion.
  - Removed throttling in workspace selector component for more immediate state feedback.
  - Updated import and clipper services to use the new synchronization waiting methods.
  - Simplified asynchronous waiting logic in indexer synchronization methods.

- **Bug Fixes**
  - Enhanced accuracy and reliability of document update and sync status indicators.

- **Tests**
  - Increased wait timeout in avatar selection test to improve stability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/components/workspace-selector/workspace-card/index.tsx

@@ -88,7 +88,7 @@ const useSyncEngineSyncProgress = (meta: WorkspaceMetadata) => {
   const engineState = useLiveData(
     useMemo(() => {
       return workspace
-        ? LiveData.from(workspace.engine.doc.state$, null).throttleTime(500)
+        ? LiveData.from(workspace.engine.doc.state$, null)
         : null;
     }, [workspace])
   );