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/FR11.e2e-spec.ts

@@ -0,0 +1,22 @@
+import { test, expect } from './global-setup';
+import { closeOptions, goToHome, setLang, showOptions } from './utils/app.utils';
+
+test.describe('Zonemaster test FR11 - [The simple view should look the same in latest version of different browsers]', () => {
+    test.beforeEach(async ({ page }) => {
+        await goToHome(page);
+        await setLang(page, 'en');
+        await page.waitForLoadState('networkidle');
+    });
+
+    test('should match the domain page', async ({ page }) => {
+        await closeOptions(page);
+        await page.waitForTimeout(400);
+        expect(await page.screenshot()).toMatchSnapshot('domain.png');
+    });
+
+    test('should not match the domain page', async ({ page }) => {
+        await showOptions(page);
+        await page.waitForTimeout(400);
+        expect(await page.screenshot()).toMatchSnapshot('domain-options.png');
+    });
+});