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/share/create_db.pl

@@ -0,0 +1,15 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use Zonemaster::Backend::Config;
+use Zonemaster::Backend::DB;
+
+my $config = Zonemaster::Backend::Config->load_config();
+my $db_engine = $config->DB_engine;
+
+my $db_class = Zonemaster::Backend::DB->get_db_class( $db_engine );
+
+my $db = $db_class->from_config( $config );
+$db->create_schema();