feat(push): smart push queueing with page-visibility fast path and app-ping/pong fallback

src/App.tsx

@@ -116,10 +116,18 @@ export function App() {
   }, [dismissInstall]);
 
   // PWA: Service worker update notification
+  // Only show banner when replacing an existing controller (real update),
+  // not on first registration when clients.claim() fires controllerchange
+  // on a previously uncontrolled page.
   useEffect(() => {
-    const handleControllerChange = () => setSwUpdateAvailable(true);
-    navigator.serviceWorker?.addEventListener('controllerchange', handleControllerChange);
-    return () => navigator.serviceWorker?.removeEventListener('controllerchange', handleControllerChange);
+    if (!navigator.serviceWorker) return;
+    let hadController = !!navigator.serviceWorker.controller;
+    const handleControllerChange = () => {
+      if (hadController) setSwUpdateAvailable(true);
+      hadController = true;
+    };
+    navigator.serviceWorker.addEventListener('controllerchange', handleControllerChange);
+    return () => navigator.serviceWorker.removeEventListener('controllerchange', handleControllerChange);
   }, []);
 
   // PWA iOS: Sync --app-height CSS variable to the true viewport height.