🤖 Fix 8s freeze: Defer auto-resume check to not block UI

PROBLEM: resumeStream IPC takes 8 seconds when resuming interrupted
streams on first launch. Even though it's async, calling it immediately
in useEffect blocks the UI from becoming interactive.

Timeline from logs:
- 1347ms: attemptResume started for cmux-stable-ids
- 9408ms: resumeStream IPC completed (8061ms blocked)

SOLUTION: Defer initial resume check with setTimeout(0), same pattern
as GitStatusStore fix.

IMPACT:
- UI becomes interactive immediately on first launch
- Auto-resume still works, just starts after React finishes mounting
- Subsequent reloads already fast (no interrupted streams to resume)

Author: ammar-agent

src/hooks/useResumeManager.ts

@@ -175,10 +175,14 @@ export function useResumeManager() {
   };
 
   useEffect(() => {
-    // Initial scan on mount - check all workspaces for interrupted streams
-    for (const [workspaceId] of workspaceStatesRef.current) {
-      void attemptResume(workspaceId);
-    }
+    // Defer initial scan to not block UI rendering
+    // Same pattern as GitStatusStore - let React finish mounting first
+    setTimeout(() => {
+      console.log(`[RENDERER] useResumeManager: Starting deferred initial check: ${performance.now()}ms`);
+      for (const [workspaceId] of workspaceStatesRef.current) {
+        void attemptResume(workspaceId);
+      }
+    }, 0);
 
     // Listen for resume check requests (primary mechanism)
     const handleResumeCheck = (event: Event) => {