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/FR25.e2e-spec.ts

@@ -0,0 +1,32 @@
+import { test, expect } from './global-setup';
+
+import { setLang } from './utils/app.utils';
+
+test.describe('Zonemaster test FR25 - [Should be able to export the result in multiple formats (HTML, CSV, JSON, TEXT)]', () => {
+    test.beforeEach(async ({ page }) => {
+        await page.goto('/');
+        await setLang(page, 'en');
+        await page.waitForLoadState('networkidle');
+    });
+
+    test('should have an export button', async ({ page }) => {
+        await page.locator('input[name="domain"]').first().focus();
+
+        await page.keyboard.type('results.afNiC.Fr');
+        await page.keyboard.press('Enter');
+
+        const exportButton = page.locator('#zmExportButton');
+        const exportContent = page.locator('#zmExportDialog');
+
+        await expect(exportButton).toBeVisible({ timeout: 10000 });
+        await expect(exportButton).toHaveText('Export');
+        await expect(exportContent).toBeHidden();
+        await exportButton.click();
+        await expect(exportContent).toBeVisible({ timeout: 1000 });
+
+        await expect(page.locator('#zmExportDialog button:nth-child(1)')).toHaveText('JSON');
+        await expect(page.locator('#zmExportDialog button:nth-child(2)')).toHaveText('HTML');
+        await expect(page.locator('#zmExportDialog button:nth-child(3)')).toHaveText('CSV');
+        await expect(page.locator('#zmExportDialog button:nth-child(4)')).toHaveText('Text');
+    });
+});