Add ESLint integration and Angular linting support

Configured ESLint for the project with Angular and TypeScript support. Added angular-eslint dependencies, updated angular.json to include linting, and created eslint.config.js for lint rules. Updated package.json and package-lock.json with new dev dependencies.

src/app/service/language.service.ts

@@ -19,14 +19,14 @@ export class LanguageService {
   use(l: Lang) {
     this.lang.set(l);
     this.translate.use(l);
-    try { localStorage.setItem(LocalStoreConstants.LANGUAGE_KEY, l); } catch {}
+    try { localStorage.setItem(LocalStoreConstants.LANGUAGE_KEY, l); } catch (e) { void e; }
   }
 
   private getInitial(): Lang {
     try {
       const stored = localStorage.getItem(LocalStoreConstants.LANGUAGE_KEY) as Lang | null;
       if (stored === 'de' || stored === 'en') return stored;
-    } catch {}
+    } catch (e) { void e; }
     const browser = (navigator.language || 'en').toLowerCase();
     return browser.startsWith('de') ? 'de' : 'en';
   }