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-engine/t/Test-nameserver01-D.t

@@ -0,0 +1,37 @@
+use Test::More;
+
+BEGIN {
+    use_ok( q{Zonemaster::Engine} );
+    use_ok( q{Zonemaster::Engine::Test::Nameserver} );
+    use_ok( q{Zonemaster::Engine::Util} );
+}
+
+my $datafile = q{t/Test-nameserver01-D.data};
+
+if ( not $ENV{ZONEMASTER_RECORD} ) {
+    die q{Stored data file missing} if not -r $datafile;
+    Zonemaster::Engine::Nameserver->restore( $datafile );
+    Zonemaster::Engine->profile->set( q{no_network}, 1 );
+}
+
+Zonemaster::Engine->add_fake_delegation(
+    'd.nameserver01.exempelvis.se' => {
+        'resolver1.exempelvis.se' => ['8.8.8.8'],
+        'resolver2.exempelvis.se' => ['9.9.9.9'],
+    },
+    fill_in_empty_oob_glue => 0,
+);
+
+my $zone = Zonemaster::Engine->zone( q{d.nameserver01.exempelvis.se} );
+
+my %res = map { $_->tag => $_ } Zonemaster::Engine::Test::Nameserver->nameserver01( $zone );
+
+ok( !$res{NO_RESPONSE},  q{should not emit NO_RESPONSE} );
+ok( $res{IS_A_RECURSOR}, q{should emit IS_A_RECURSOR} );
+ok( !$res{NO_RECURSOR},  q{should not emit NO_RECURSOR} );
+
+if ( $ENV{ZONEMASTER_RECORD} ) {
+    Zonemaster::Engine::Nameserver->save( $datafile );
+}
+
+done_testing;