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-ldns/t/axfr.t

@@ -0,0 +1,29 @@
+use Test::More;
+use Test::Fatal;
+
+BEGIN { use_ok( 'Zonemaster::LDNS' ) }
+
+SKIP: {
+    skip 'no network', 3 unless $ENV{TEST_WITH_NETWORK};
+
+    my $res = Zonemaster::LDNS->new( '46.21.106.227' );
+    my $res2 = Zonemaster::LDNS->new( '192.36.144.107' );
+
+    my $counter = 0;
+    my $return = $res->axfr( 'cyberpomo.com',
+        sub {
+            my ($rr) = @_;
+            $counter += 1;
+            if ($rr->type eq 'CNAME') {
+                return 0;
+            } else {
+                return 1;
+            }
+        });
+    ok(!$return, 'Terminated early');
+    ok(($counter > 1), 'Saw more than one entry (' . $counter . ')');
+
+    like( exception { $res2->axfr( 'iis.se', sub { return 1 })}, qr/NOTAUTH/, 'Expected exception');
+}
+
+done_testing;