Lots of technical improvements

src/app/app.config.ts

@@ -1,9 +1,10 @@
-import {ApplicationConfig, inject, provideAppInitializer, provideBrowserGlobalErrorListeners, provideZonelessChangeDetection} from '@angular/core';
+import {ApplicationConfig, inject, isDevMode, provideAppInitializer, provideBrowserGlobalErrorListeners, provideZonelessChangeDetection} from '@angular/core';
 import { provideRouter, withInMemoryScrolling  } from '@angular/router';
 
 import { routes } from './app.routes';
 import {provideAnimations} from '@angular/platform-browser/animations';
 import {provideHttpClient} from '@angular/common/http';
+import {provideServiceWorker} from '@angular/service-worker';
 import {provideTranslateService} from '@ngx-translate/core';
 import {provideTranslateHttpLoader} from '@ngx-translate/http-loader';
 import {LocalStoreConstants} from './constants/LocalStoreConstants';
@@ -47,11 +48,15 @@ export const appConfig: ApplicationConfig = {
          sanitizer.bypassSecurityTrustResourceUrl('assets/logos/linkedIn.svg')
       );
     }),
+    provideServiceWorker('ngsw-worker.js', {
+      enabled: !isDevMode(),
+      registrationStrategy: 'registerWhenStable:30000'
+    }),
   ]
 };
 
 function getInitialLang(): string {
-  const saved = localStorage.getItem(LocalStoreConstants.LANGUAGE_KEY);
+  const saved = typeof localStorage !== 'undefined' ? localStorage.getItem(LocalStoreConstants.LANGUAGE_KEY) : null;
   if (saved) return saved;
   const nav = typeof navigator !== 'undefined' ? navigator.language?.toLowerCase() : 'en';
   return nav?.startsWith('de') ? 'de' : 'en';