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/README.md

@@ -0,0 +1,66 @@
+# Zonemaster Engine
+
+## Purpose
+
+This repository holds one of the components of the Zonemaster product. For an
+overview of the Zonemaster software, please see the
+[Zonemaster main repository].
+
+This Git repository contains the *Zonemaster Engine testing framework*,
+and contains all code needed to perform the full suite of Zonemaster
+tests.
+
+## Prerequisites
+
+For supported processor architectures, operating systems and Perl versions see
+[Zonemaster/README.md].
+
+## Installation
+
+Installation instructions for the Engine is provided in the
+[installation] document.
+
+## Configuration
+
+This repository does not need any specific configuration.
+
+## Docker
+
+Zonemaster-CLI is available on [Docker Hub], and can be conveniently downloaded
+and run without any installation. See [USING] Zonemaster-CLI for how to run
+Zonemaster-CLI on Docker.
+
+To build your own Docker image, see the [Docker Image Creation] documentation.
+
+
+## Documentation
+
+There is full POD coverage of the Perl code. The documentation can be
+read on the [CPAN site].
+
+Documentation on Zonemaster-Engine is also found under the [docs] directory.
+
+
+## Participation, Contact and Bug reporting
+
+For participation, contact and bug reporting, please see
+[Zonemaster/README.md](https://github.com/zonemaster/zonemaster/blob/master/README.md).
+
+
+## License
+
+This is free software under a 2-clause BSD license. The full text of the license can
+be found in the [LICENSE](LICENSE) file included in this repository.
+
+
+[CPAN site]:                                      https://metacpan.org/pod/Zonemaster::Engine
+[Docker Hub]:                                     https://hub.docker.com/u/zonemaster
+[Docker Image Creation]:                          https://github.com/zonemaster/zonemaster/blob/master/docs/internal/maintenance/ReleaseProcess-create-docker-image.md
+[Docs]:                                           docs/
+[Installation]:                                   https://github.com/zonemaster/zonemaster/blob/master/docs/public/installation/zonemaster-engine.md
+[USING]:                                          https://github.com/zonemaster/zonemaster/blob/master/docs/public/using/cli.md
+[Zonemaster main repository]:                     https://github.com/zonemaster/zonemaster
+[Zonemaster/README.md]:                           https://github.com/zonemaster/zonemaster/blob/master/README.md
+
+
+