feat: add full Zonemaster stack with Docker and Spanish UI

- Clone all 5 Zonemaster component repos (LDNS, Engine, CLI, Backend, GUI)
- Dockerfile.backend: 8-stage multi-stage build LDNS→Engine→CLI→Backend
- Dockerfile.gui: Astro static build served via nginx
- docker-compose.yml: backend (internal) + frontend (port 5353)
- nginx.conf: root redirects to /es/, /api/ proxied to backend
- zonemaster-gui/config.ts: defaultLanguage set to 'es' (Spanish)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

zonemaster-gui/e2e/FR04.e2e-spec.ts

@@ -0,0 +1,14 @@
+import { test, expect } from './global-setup';
+
+import { goToHome, setLang } from './utils/app.utils';
+
+test.describe('Zonemaster test FR04 - Valid title for the Web interface', () => {
+  test.beforeEach(async ({ page }) => {
+    await goToHome(page);
+    await setLang(page, 'en');
+  });
+
+  test('should have right title - Zonemaster', async ({ page }) => {
+    await expect(page).toHaveTitle('Zonemaster');
+  });
+});