fix: Memory-Leak bei PWA-Update-Checks durch Cleanup beheben.

Entfernt Listener und Intervalle beim erneuten SW-Register und beim Unmount des Hooks.

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

client/src/hooks/usePwaUpdate.ts

@@ -1,34 +1,51 @@
+import { useEffect, useRef } from 'react'
 import { useRegisterSW } from 'virtual:pwa-register/react'
 
 const UPDATE_CHECK_INTERVAL_MS = 60 * 60 * 1000
 
-function scheduleUpdateChecks(registration: ServiceWorkerRegistration) {
+function scheduleUpdateChecks(registration: ServiceWorkerRegistration): () => void {
   const checkForUpdate = () => {
     registration.update().catch(() => {})
   }
 
-  document.addEventListener('visibilitychange', () => {
+  const onVisibilityChange = () => {
     if (document.visibilityState === 'visible') {
       checkForUpdate()
     }
-  })
+  }
 
-  window.setInterval(checkForUpdate, UPDATE_CHECK_INTERVAL_MS)
+  document.addEventListener('visibilitychange', onVisibilityChange)
+  const intervalId = window.setInterval(checkForUpdate, UPDATE_CHECK_INTERVAL_MS)
+
+  return () => {
+    document.removeEventListener('visibilitychange', onVisibilityChange)
+    window.clearInterval(intervalId)
+  }
 }
 
 export function usePwaUpdate() {
+  const cleanupRef = useRef<(() => void) | null>(null)
+
   const {
     needRefresh: [needRefresh],
     updateServiceWorker
   } = useRegisterSW({
     immediate: true,
     onRegisteredSW(_swUrl: string, registration: ServiceWorkerRegistration | undefined) {
-      if (registration) {
+      if (!registration) return
-        scheduleUpdateChecks(registration)
+
-      }
+      cleanupRef.current?.()
+      cleanupRef.current = scheduleUpdateChecks(registration)
     }
   })
 
+  useEffect(() => {
+    return () => {
+      cleanupRef.current?.()
+      cleanupRef.current = null
+    }
+  }, [])
+
   const updateApp = async () => {
     await updateServiceWorker(true)
   }