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/lib/Zonemaster/LDNS/RR/NSEC3.pm

@@ -0,0 +1,62 @@
+package Zonemaster::LDNS::RR::NSEC3;
+
+use strict;
+use warnings;
+
+use parent 'Zonemaster::LDNS::RR';
+
+1;
+
+=head1 NAME
+
+Zonemaster::LDNS::RR::NSEC3 - Type NSEC3 record
+
+=head1 DESCRIPTION
+
+A subclass of L<Zonemaster::LDNS::RR>, so it has all the methods of that class available in addition to the ones documented here.
+
+=head1 METHODS
+
+=over
+
+=item algorithm()
+
+Returns the algorithm number.
+
+=item flags()
+
+Returns the flags field.
+
+=item optout()
+
+Returns the optout flag.
+
+=item iterations()
+
+Returns the iteration count.
+
+=item salt()
+
+Returns the contents of the salt field as a binary string, if non-empty; otherwise, returns an empty string. If there was a problem accessing the salt field, returns undef.
+
+=item next_owner()
+
+Returns the next hashed owner name field, in binary form. To convert the return value to the human-readable presentation format, use L<MIME::Base32/encode_base32hex>.
+
+=item typelist()
+
+Returns the typelist as a space-separated string.
+
+=item typehref()
+
+Returns the typelist as a reference to a hash where the included types are keys storing true values.
+
+=item covers($name)
+
+Returns true or false depending on if the record covers the given name or not.
+
+=item hash_name($name)
+
+Computes and returns a hash, in canonical form, of the given name using the parameters (algorithm, iterations, salt) of the resource record.
+
+=back