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/MethodsV2/child.parent.child-ns-cname-3.methodsv2.xa.zone

@@ -0,0 +1,15 @@
+$ORIGIN child.parent.child-ns-cname-3.methodsv2.xa.
+$TTL 3600
+
+@       SOA     ns1-cname admin. (
+                2024071205      ; serial
+                6h              ; refresh
+                1h              ; retry
+                1w              ; expire
+                1d )            ; minimum
+
+@		NS	ns3-cname.child-ns-cname-3.methodsv2.xa.
+@		NS	ns4-cname.child-ns-cname-3.methodsv2.xa.
+
+; EOF
+