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/README-Bind.md

@@ -0,0 +1,23 @@
+# Bind
+
+## Generate DNS records
+
+For this test case Bind is used for generating some DNS records, and then
+they are added to the CoreDNS configuration. Specifically `DNSKEY`, `NSEC`,
+`NSEC3`, `NSEC3PARAM` and `RRSIG` records are generated and then copied to,
+for this test case, [dnssec10.cfg](dnssec10.cfg).
+
+Bind is never used to serve the test zones. That is done by CoreDNS, and in the
+future maybe IBDNS. 
+
+## Creating new scenarios or updating existing scenarios
+
+The recommended path is to let Bind load the zone for the scenario and then get
+the records from responses on queries to the bind specific IP addresses,
+127.15.10.37 and in some cases 127.15.10.38. That will give valid DNSKEY, NSEC,
+NSEC3 and NSEC3PARAM records signed by valid RRSIG.
+
+After that manipulations could be necessary. See existing test zones for examples.
+
+Go to the [Bind](Bind) directory for Bind configuration, zone files and more
+information.