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.server.ts

@@ -0,0 +1,8 @@
+import { mergeApplicationConfig } from '@angular/core';
+import { provideServerRendering, withRoutes } from '@angular/ssr';
+import { appConfig } from './app.config';
+import { serverRoutes } from './app.routes.server';
+
+export const serverConfig = mergeApplicationConfig(appConfig, {
+  providers: [provideServerRendering(withRoutes(serverRoutes))],
+});