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/Consistency-TP/consistency06/consistency06.xb.zone

@@ -0,0 +1,29 @@
+$ORIGIN consistency06.xa.
+$TTL 3600
+
+@       SOA     ns1 admin. (
+                2024051803      ; serial
+                6h              ; refresh
+                1h              ; retry
+                1w              ; expire
+                1d )            ; minimum
+
+        NS    ns1
+        NS    ns2
+
+ns1     A     127.14.6.23
+ns1     AAAA  fda1:b2:c3:0:127:14:6:23
+ns2     A     127.14.6.24
+ns2     AAAA  fda1:b2:c3:0:127:14:6:24
+
+$ORIGIN mult-soa-mnames-no-del-undel-2.consistency06.xb.
+; No delegation
+ns3     A       127.14.6.33
+ns3     AAAA    fda1:b2:c3:0:127:14:6:33
+ns4     A       127.14.6.34
+ns4     AAAA    fda1:b2:c3:0:127:14:6:34
+
+
+; EOF
+
+