Batch workspace metadata updates on initial load

When subscribing to metadata, backend sends one event per workspace
synchronously. This was causing N re-renders for N workspaces.

Now we batch these updates using queueMicrotask - all synchronous
events are collected and flushed in a single state update after the
current task completes. This reduces 19 re-renders to 1 on startup.

Author: ammar-agent

src/hooks/useWorkspaceManagement.ts

@@ -41,12 +41,34 @@ export function useWorkspaceManagement({
     // Subscribe to workspace metadata updates
     // NOTE: onMetadata sends all current metadata immediately upon subscription,
     // then sends updates as they happen (e.g., from renames)
+    
+    // Batch updates to avoid triggering re-renders for each workspace on initial load
+    let pendingUpdates = new Map<string, FrontendWorkspaceMetadata>();
+    let batchScheduled = false;
+
+    const flushBatch = () => {
+      if (pendingUpdates.size > 0) {
+        const updates = pendingUpdates;
+        pendingUpdates = new Map();
+        batchScheduled = false;
+        
+        setWorkspaceMetadata((prev) => {
+          const updated = new Map(prev);
+          for (const [id, metadata] of updates) {
+            updated.set(id, metadata);
+          }
+          return updated;
+        });
+      }
+    };
+
     const unsubscribe = window.api.workspace.onMetadata((event: { workspaceId: string; metadata: FrontendWorkspaceMetadata }) => {
-      setWorkspaceMetadata((prev) => {
-        const updated = new Map(prev);
-        updated.set(event.workspaceId, event.metadata);
-        return updated;
-      });
+      pendingUpdates.set(event.workspaceId, event.metadata);
+      
+      if (!batchScheduled) {
+        batchScheduled = true;
+        queueMicrotask(flushBatch);
+      }
     });
 
     return () => {