feat: PWA-Updates erkennen und Nutzer zum Reload auffordern.

Wechselt auf prompt-Modus mit Update-Banner, periodischer SW-Prüfung und no-cache-Headern für Service Worker und index.html.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/hooks/usePwaUpdate.ts

@@ -0,0 +1,37 @@
+import { useRegisterSW } from 'virtual:pwa-register/react'
+
+const UPDATE_CHECK_INTERVAL_MS = 60 * 60 * 1000
+
+function scheduleUpdateChecks(registration: ServiceWorkerRegistration) {
+  const checkForUpdate = () => {
+    registration.update().catch(() => {})
+  }
+
+  document.addEventListener('visibilitychange', () => {
+    if (document.visibilityState === 'visible') {
+      checkForUpdate()
+    }
+  })
+
+  window.setInterval(checkForUpdate, UPDATE_CHECK_INTERVAL_MS)
+}
+
+export function usePwaUpdate() {
+  const {
+    needRefresh: [needRefresh],
+    updateServiceWorker
+  } = useRegisterSW({
+    immediate: true,
+    onRegisteredSW(_swUrl: string, registration: ServiceWorkerRegistration | undefined) {
+      if (registration) {
+        scheduleUpdateChecks(registration)
+      }
+    }
+  })
+
+  const updateApp = async () => {
+    await updateServiceWorker(true)
+  }
+
+  return { needRefresh, updateApp }
+}