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-backend/.gitignore

@@ -0,0 +1,25 @@
+/Makefile
+Makefile.old
+Build
+Build.bat
+META.*
+MYMETA.*
+.build/
+_build/
+cover_db/
+blib/
+.lwpcookies
+.last_cover_stats
+nytprof.out
+pod2htm*.tmp
+pm_to_blib
+Zonemaster-*
+Zonemaster-*.tar.gz
+.orig
+inc
+*.mo
+
+# Ignore Emacs and other backup files
+*.bak
+*~
+.*.swp