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/static/config.json

@@ -0,0 +1,11 @@
+{
+    "msgBanner": {
+        "en": "",
+        "sv": "",
+        "da": "",
+        "es": "",
+        "fi": "",
+        "fr": "",
+        "nb": ""
+    }
+}