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/patch/patch_db_zonemaster_backend_ver_11.2.0.pl

@@ -0,0 +1,32 @@
+use strict;
+use warnings;
+
+use Zonemaster::Backend::Config;
+use Zonemaster::Engine;
+
+my $config = Zonemaster::Backend::Config->load_config();
+
+my $db_engine = $config->DB_engine;
+print "Configured database engine: $db_engine\n";
+
+if ( $db_engine =~ /^(MySQL|PostgreSQL|SQLite)$/ ) {
+    print( "Starting database migration\n" );
+
+    _update_result_entries( $config->new_DB()->dbh() );
+
+    print( "\nMigration done\n" );
+}
+else {
+    die "Unknown database engine configured: $db_engine\n";
+}
+
+
+sub _update_result_entries {
+    my ( $dbh ) = @_;
+
+    $dbh->do(<<SQL) or die 'Migration failed';
+        UPDATE result_entries
+           SET module = 'Backend'
+         WHERE upper(module) = 'BACKEND_TEST_AGENT';
+SQL
+}