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/docs/public/specifications/tests/Connectivity-TP/README.md

@@ -0,0 +1,18 @@
+# Connectivity Test Plan
+
+This document uses the terminology defined in the [Master Test Plan].
+
+
+[Master Test Plan]:             ../MasterTestPlan.md
+[Test Case README]:             ../README.md
+
+<!-- Content until EOF generated by script updateTestPlanReadme.pl from Zonemaster/Zonemaster utils directory -->
+
+## Test cases list
+
+|Test Case |Test Case Description|
+|:---------|:--------------------|
+|[CONNECTIVITY01](connectivity01.md)|UDP connectivity to name servers|
+|[CONNECTIVITY02](connectivity02.md)|TCP connectivity to name servers|
+|[CONNECTIVITY03](connectivity03.md)|AS Diversity|
+|[CONNECTIVITY04](connectivity04.md)|IP Prefix Diversity|