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/DNSSEC-TP/dnssec10/Bind/zones/good-nsec3-1.dnssec10.xa.zone

@@ -0,0 +1,17 @@
+$ORIGIN good-nsec3-1.dnssec10.xa.
+;
+$TTL   86400
+@   IN   SOA   localhost. root.localhost. (
+               9          ; Serial
+               3600       ; Refresh
+               1200       ; Retry
+               2419200    ; Expire
+               604800 )   ; Negative Cache TTL
+;
+@       NS    ns1
+@       NS    ns2
+
+ns1     A     127.15.10.31
+ns1     AAAA  fda1:b2:c3:0:127:15:10:31
+ns2     A     127.15.10.32
+ns2     AAAA  fda1:b2:c3:0:127:15:10:32