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/FR21.e2e-spec.ts

@@ -0,0 +1,55 @@
+import { test, expect } from './global-setup';
+import { goToHome, setLang, setupApiMocks } from './utils/app.utils';
+import type { Page } from '@playwright/test';
+
+test.describe.serial('Zonemaster test FR21 - [Able to provide a summarized result of the test being run ' +
+    '(possibility in different colours for error, warning, success etc.)]', () => {
+
+    let page: Page;
+
+    // Keep the same page between tests
+    test.beforeAll(async ({ browser }) => {
+        page = await browser.newPage();
+        await setupApiMocks(page);
+        await goToHome(page);
+        await setLang(page, 'en');
+        await page.waitForLoadState('networkidle');
+    });
+
+    test('should display summary', async () => {
+        await expect(page.locator('.zm-domain-test__progress-bar')).toHaveCount(0);
+        await page.locator('input[name="domain"]').first().focus();
+
+        await page.keyboard.type('results.afNiC.Fr');
+        await page.keyboard.press('Enter');
+
+        await expect(page.locator('.zm-result')).toBeVisible({ timeout: 10000 });
+
+        const messageCountBadges = page.locator('.zm-filter-toggle');
+        const expectedLabels = ['All', 'Info', 'Notice', 'Warning', 'Error', 'Critical'];
+
+        await expect(messageCountBadges).toHaveCount(expectedLabels.length);
+
+        for (const [idx, label] of expectedLabels.entries()) {
+            await expect(messageCountBadges.nth(idx)).toContainText(label);
+        }
+    });
+
+    test('should display number of each level', async () => {
+        await expect(page.locator('.zm-filter-toggle__badge:not(:empty)')).toHaveCount(6);
+    });
+
+    test('should display summary with good colors', async () => {
+        const filterButtons = page.locator('.zm-filter-toggle input[type="checkbox"]');
+
+        for (const idx of [1, 2, 3, 4, 5]) {
+            await filterButtons.nth(idx).click();
+        }
+
+        // wait for .2 second (color transition)
+        await page.waitForTimeout(200);
+
+
+        expect(await page.screenshot()).toMatchSnapshot('results.png');
+    });
+});