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>

nginx.conf

@@ -0,0 +1,33 @@
+server {
+    listen 80;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # Redirect root to Spanish
+    location = / {
+        return 301 /es/;
+    }
+
+    # Proxy API calls to the backend service
+    location /api/ {
+        proxy_pass http://backend:5000/;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    }
+
+    # Rewrite /{lang}/result/{id} to /{lang}/result/id/index.html
+    location ~ ^/([^/]+)/result/[^/]+/?$ {
+        set $lang $1;
+        try_files /$lang/result/id/index.html =404;
+    }
+
+    # Rewrite /result/{id} to /es/result/id/index.html
+    location ~ ^/result/[^/]+/?$ {
+        try_files /es/result/id/index.html =404;
+    }
+
+    location / {
+        try_files $uri $uri/ =404;
+    }
+}