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/lib/Zonemaster/Engine/Nameserver/Cache.pm

@@ -0,0 +1,99 @@
+package Zonemaster::Engine::Nameserver::Cache;
+
+use v5.16.0;
+use warnings;
+
+use version; our $VERSION = version->declare("v1.0.4");
+
+use Class::Accessor "antlers";
+
+our %object_cache;
+
+has 'data' => ( is => 'ro' );
+has 'address' => ( is => 'ro' );
+
+sub get_cache_type {
+    my ( $class, $profile ) = @_;
+    my $cache_type = 'LocalCache';
+
+    my %cache_config = %{ $profile->get( 'cache' ) };
+
+    if ( exists $cache_config{'redis'} ) {
+        $cache_type = 'RedisCache';
+    }
+
+    return $cache_type;
+}
+
+sub get_cache_class {
+    my ( $class, $cache_type ) = @_;
+
+    my $cache_class = "Zonemaster::Engine::Nameserver::Cache::$cache_type";
+
+    require ( "$cache_class.pm" =~ s{::}{/}gr );
+    $cache_class->import();
+
+    return $cache_class;
+}
+
+sub empty_cache {
+    %object_cache = ();
+
+    return;
+}
+
+1;
+
+=head1 NAME
+
+Zonemaster::Engine::Nameserver::Cache - shared caches for nameserver objects
+
+=head1 SYNOPSIS
+
+    This class should not be used directly.
+
+=head1 ATTRIBUTES
+
+=over
+
+=item address
+
+A L<Net::IP::XS> object holding the nameserver's address.
+
+=item data
+
+A reference to a hash holding the cache of sent queries. Not meant for external use.
+
+=back
+
+=head1 CLASS METHODS
+
+=over
+
+=item get_cache_type()
+
+    my $cache_type = get_cache_type( Zonemaster::Engine::Profile->effective );
+
+Get the cache type value from the profile, i.e. the name of the cache module to use.
+
+Takes a L<Zonemaster::Engine::Profile> object.
+
+Returns a string.
+
+=item get_cache_class()
+
+    my $cache_class = get_cache_class( 'LocalCache' );
+
+Get the cache adapter class for the given database type.
+
+Takes a string (cache database type).
+
+Returns a string, or throws an exception if the cache adapter class cannot be loaded.
+
+=item empty_cache()
+
+Clear the cache.
+
+=back
+
+=cut