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/FR18.e2e-spec.ts

@@ -0,0 +1,22 @@
+import {test, expect} from './global-setup';
+
+import {goToHome, setLang} from './utils/app.utils';
+
+test.describe('Zonemaster test FR18 - [The GUI should be able to run tests by just providing the domain name]', () => {
+    test.beforeEach(async ({page}) => {
+        await goToHome(page);
+        await setLang(page, 'en');
+    });
+
+    test('should display progress bar', async ({page}) => {
+        await page.waitForLoadState('networkidle');
+
+        await expect(page.locator('.zm-domain-test__progress-bar')).toHaveCount(0);
+        await page.locator('input[name="domain"]').first().focus();
+
+        await page.keyboard.type('progress.afNiC.Fr');
+        await page.keyboard.press('Enter');
+
+        await expect(page.locator('.zm-domain-test__progress-bar')).toHaveCount(1);
+    });
+});