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/consistency05/ns1.COMMON.consistency05.xa.zone

@@ -0,0 +1,21 @@
+; This zone file is common for several sub-zones to consistency05.xa. Note that
+;
+; * $ORIGIN must not be set here,
+; * All names must be relative
+; * Only ns1 in this zone file
+
+$TTL 3600
+
+@       SOA     ns1 admin.mail.xa. (
+                2023092000      ; serial
+                6h              ; refresh
+                1h              ; retry
+                1w              ; expire
+                1d )            ; minimum
+
+        NS      ns1
+
+ns1     A       127.14.5.31
+ns1     AAAA    fda1:b2:c3::127:14:5:31
+
+;EOF