feat(app): add prerender, self-hosted fonts and privacy page

Fonts come from npm, not Google, so no third-party font requests.
Pages are prerendered at build time; browser-only code is guarded.
nginx serves per-route HTML, a real 404 and gzip.

src/app/app.config.ts

@@ -3,7 +3,7 @@ import { provideRouter, withInMemoryScrolling  } from '@angular/router';
 
 import { routes } from './app.routes';
 import {provideAnimations} from '@angular/platform-browser/animations';
-import {provideHttpClient, withXhr} from '@angular/common/http';
+import {provideHttpClient, withFetch} from '@angular/common/http';
 import {provideServiceWorker} from '@angular/service-worker';
 import {provideTranslateService} from '@ngx-translate/core';
 import {provideTranslateHttpLoader} from '@ngx-translate/http-loader';
@@ -25,7 +25,7 @@ export const appConfig: ApplicationConfig = {
         anchorScrolling: 'enabled'
       })),
     provideAnimations(),
-    provideHttpClient(withXhr()),
+    provideHttpClient(withFetch()),
     provideTranslateService({
       lang: INITIAL_LANG,
       fallbackLang: 'en',