feat: implement cross-tab logout synchronization using storage event broadcasting

src/app/logout/page.tsx

@@ -13,6 +13,9 @@ export default function LogoutPage() {
     localStorage.setItem('isLoggingOut', 'true');
     localStorage.removeItem('accessToken');
     localStorage.removeItem('refreshToken');
+    // Broadcast to other open tabs so they also log out.
+    // 'storage' events only fire in OTHER tabs, not the one that wrote the value.
+    localStorage.setItem('re-quest-logout-broadcast', String(Date.now()));
   }
 
   useEffect(() => {