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/t/queue.t

@@ -0,0 +1,86 @@
+use strict;
+use warnings;
+use 5.14.2;
+
+use Test::More tests => 2;
+use Test::NoWarnings;
+use Log::Any::Test;
+
+use File::Basename        qw( dirname );
+use File::Spec::Functions qw( rel2abs );
+use File::Temp            qw( tempdir );
+use Log::Any              qw( $log );
+use Test::Differences;
+use Test::Exception;
+use Zonemaster::Backend::Config;
+use Zonemaster::Backend::DB qw( $TEST_RUNNING );
+use Zonemaster::Engine;
+
+my $t_path;
+BEGIN {
+    $t_path = dirname( rel2abs( $0 ) );
+}
+use lib $t_path;
+use TestUtil;
+
+my $db_backend = TestUtil::db_backend();
+my $tempdir    = tempdir( CLEANUP => 1 );
+my $config     = Zonemaster::Backend::Config->parse( <<EOF );
+[DB]
+engine = $db_backend
+
+[MYSQL]
+host     = localhost
+user     = zonemaster_test
+password = zonemaster
+database = zonemaster_test
+
+[POSTGRESQL]
+host     = localhost
+user     = zonemaster_test
+password = zonemaster
+database = zonemaster_test
+
+[SQLITE]
+database_file = $tempdir/zonemaster.sqlite
+
+[ZONEMASTER]
+age_reuse_previous_test = 10
+EOF
+
+subtest 'Everything but Test::NoWarnings' => sub {
+    lives_ok {    # Make sure we get to print log messages in case of errors.
+        my $db = TestUtil::init_db( $config );
+
+        subtest 'Claiming waiting tests for processing' => sub {
+            eq_or_diff
+              [ $db->get_test_request( undef ) ],
+              [ undef, undef ],
+              "An empty list is returned when queue is empty";
+
+            my $testid1 = $db->create_new_test( "1.claim.test", {}, 10 );
+            eq_or_diff
+              [ $db->get_test_request( undef ) ],
+              [ $testid1, undef ],
+              "A waiting test is returned if one is available";
+            eq_or_diff
+              [ $db->get_test_request( undef ) ],
+              [ undef, undef ],
+              "Claimed test is removed from queue";
+            is
+              $db->test_state( $testid1 ),
+              $TEST_RUNNING,
+              "Claimed test is in 'running' state";
+        };
+    };
+};
+
+for my $msg ( @{ $log->msgs } ) {
+    my $text = sprintf( "%s: %s", $msg->{level}, $msg->{message} );
+    if ( $msg->{level} =~ /trace|debug|info|notice/ ) {
+        note $text;
+    }
+    else {
+        diag $text;
+    }
+}