🤖 fix: improve code review auto-refresh reliability in Electron (#1268)

Add window.focus event listener alongside visibilitychange to handle
cases where the Electron app loses/gains focus without the document
becoming hidden (e.g., app behind other windows, different
desktop/space).

The visibilitychange API is designed for browser tab visibility, which
doesn't map perfectly to Electron window focus states. Adding the focus
event ensures pending refreshes are flushed when the user returns to the
app regardless of how they left.

---
_Generated with `mux` • Model: `anthropic:claude-opus-4-5` • Thinking:
`high`_

Author: ammar-agent

src/browser/hooks/useReviewRefreshController.test.ts

@@ -59,7 +59,9 @@ describe("useReviewRefreshController design", () => {
 
   test("visibility contract: hidden tab queues refresh for later", () => {
     // Contract: When document.hidden is true, refresh is queued.
-    // When visibilitychange fires and document.hidden becomes false, queued refresh executes.
+    // When visibilitychange fires or window.focus fires (and document is visible),
+    // queued refresh executes. Uses both events since visibilitychange alone is
+    // unreliable in Electron when app is behind other windows or on different desktop.
     // This prevents wasted git operations when user isn't looking.
     expect(true).toBe(true);
   });

src/browser/hooks/useReviewRefreshController.ts

@@ -238,17 +238,23 @@ export function useReviewRefreshController(
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [api, workspaceId, isCreating]);
 
-  // Handle visibility changes - flush pending refresh when tab becomes visible
+  // Handle visibility/focus changes - flush pending refresh when user returns.
+  // Uses both visibilitychange (for browser tab hidden state) and window focus
+  // (for Electron app focus) since visibilitychange alone is unreliable in Electron
+  // when the app is behind other windows or on a different desktop/space.
   useEffect(() => {
-    const handleVisibilityChange = () => {
+    const handleReturn = () => {
+      // Only flush if document is actually visible
       if (!document.hidden) {
         flushPending("hidden");
       }
     };
 
-    document.addEventListener("visibilitychange", handleVisibilityChange);
+    document.addEventListener("visibilitychange", handleReturn);
+    window.addEventListener("focus", handleReturn);
     return () => {
-      document.removeEventListener("visibilitychange", handleVisibilityChange);
+      document.removeEventListener("visibilitychange", handleReturn);
+      window.removeEventListener("focus", handleReturn);
     };
     // flushPending is stable (only uses refs internally)
     // eslint-disable-next-line react-hooks/exhaustive-deps