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/test-zone-data/Address-TP/address03/no-ns-have-ptr.address03.xa.zone

@@ -0,0 +1,12 @@
+$ORIGIN no-ns-have-ptr.address03.xa. ; Must end with "."
+$TTL 3600
+
+@       SOA     ns4.child.address03.xa. admin. (
+                2025022400      ; serial
+                6h              ; refresh
+                1h              ; retry
+                1w              ; expire
+                1d )            ; minimum
+
+                NS	ns4.child.address03.xa.
+                NS	ns5.child.address03.xa.