Fix: Add storesSynced state to prevent render before sync

Problem: syncWorkspaces runs in useEffect AFTER render, but sidebar
components access the store DURING render, causing assertion failures.

Solution: Add storesSynced state that only becomes true after
syncWorkspaces completes. Gate UI rendering on both metadataLoading
AND storesSynced to ensure stores are ready before any component
tries to access them.

Author: ammar-agent

src/App.tsx

@@ -114,24 +114,26 @@ function AppInner() {
   const workspaceStore = useWorkspaceStoreRaw();
   const gitStatusStore = useGitStatusStoreRaw();
 
+  // Track whether stores have been synced (separate from metadata loading)
+  const [storesSynced, setStoresSynced] = useState(false);
+
   useEffect(() => {
     if (!metadataLoading) {
       workspaceStore.syncWorkspaces(workspaceMetadata);
       gitStatusStore.syncWorkspaces(workspaceMetadata);
+      setStoresSynced(true);
+    } else {
+      setStoresSynced(false);
     }
   }, [metadataLoading, workspaceMetadata, workspaceStore, gitStatusStore]);
 
   // Validate selectedWorkspace when metadata changes
   // Clear selection if workspace was deleted
   useEffect(() => {
-    if (
-      !metadataLoading &&
-      selectedWorkspace &&
-      !workspaceMetadata.has(selectedWorkspace.workspaceId)
-    ) {
+    if (storesSynced && selectedWorkspace && !workspaceMetadata.has(selectedWorkspace.workspaceId)) {
       setSelectedWorkspace(null);
     }
-  }, [metadataLoading, selectedWorkspace, workspaceMetadata, setSelectedWorkspace]);
+  }, [storesSynced, selectedWorkspace, workspaceMetadata, setSelectedWorkspace]);
 
   // Track last-read timestamps for unread indicators
   const { lastReadTimestamps, onToggleUnread } = useUnreadTracking(selectedWorkspace);
@@ -672,9 +674,9 @@ function AppInner() {
       );
   }, [projects, setSelectedWorkspace, setWorkspaceMetadata]);
 
-  // CRITICAL: Don't render workspace UI until metadata loads and stores are synced
+  // CRITICAL: Don't render workspace UI until metadata loads AND stores are synced
   // This ensures WorkspaceStore.addWorkspace() is called before any component accesses workspaces
-  if (metadataLoading) {
+  if (metadataLoading || !storesSynced) {
     return <LoadingScreen />;
   }