fix legacy service-worker issue

packages/frontend/src/app/app.config.ts

@@ -33,6 +33,7 @@ import {
     MAT_DATE_LOCALE,
 } from '@angular/material/core';
 import { MAT_FORM_FIELD_DEFAULT_OPTIONS } from '@angular/material/form-field';
+import { provideServiceWorker } from '@angular/service-worker';
 import { de } from 'date-fns/locale';
 import { routes } from './app.routes';
 import { initializeApi } from './util/api';
@@ -88,5 +89,9 @@ export const appConfig: ApplicationConfig = {
         },
         { provide: MAT_DATE_FORMATS, useValue: MAT_DATE_FNS_FORMATS },
         { provide: MAT_DATE_LOCALE, useValue: de },
+        provideServiceWorker('ngsw-worker.js', {
+            enabled: !isDevMode(),
+            registrationStrategy: 'registerWhenStable:30000',
+        }),
     ],
 };