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/docs/internal/design/Profiles.md

@@ -0,0 +1,52 @@
+# Profiles
+
+## Overview
+
+Profiles is a configuration format and feature of Zonemaster Engine.
+Each of Zonemaster CLI, Backend and GUI allow users and administrators to configure Zonemaster Engine with different profiles.
+
+This document provides a high-level view of how profiles are applied across the different Zonemaster components.
+For details on how profiles integrate with a given component, refer to the respective component documentations.
+Links to the relevant sections are provided below.
+
+
+## Background
+
+The Zonemaster requirements and specification documents speak of user-configurable profiles and policies 
+for Zonemaster Engine and CLI.
+
+In release v2018.2 all of the configurable features "config", "filter", "policy" and "profile" from the 
+requirements and specifications were integrated into a single data structure, also called "profile".
+
+
+## Profiles in Zonemaster Engine
+
+Zonemaster Engine has an effective profile that guides how it performs its tests and analyzes their results.
+It comes with a sensible default profile while allowing applications to override the default behavior.
+This is described in greater detail in the [Zonemaster::Engine::Profile] documentation.
+
+
+## Profiles in Zonemaster Backend
+
+Zonemaster Backend allows its administrators to configure available profiles for its users to choose from.
+Configuration is described in greater detail in the [Zonemaster Backend configuration] documentation.
+The [Zonemaster Backend RPC-API] documentation lists methods that accept profile name arguments.
+
+
+## Profiles in Zonemaster CLI
+
+Zonemaster CLI allows users to specify the path to a profile to be used when starting a test.
+If no profile is specified, the Zonemaster Engine default profile is used.
+
+
+## Profiles in Zonemaster GUI
+
+Zonemaster GUI allows the user select profile from a set of choices.
+The available profile choices are configured in a JSON file that maps profile name strings to description strings.
+
+
+-------
+[Zonemaster Backend RPC-API]: ../../public/using/backend/rpcapi-reference.md
+[Zonemaster Backend configuration]: ../../public/configuration/backend.md#public-profiles-and-private-profiles-sections
+[Zonemaster::Engine::Profile]: https://metacpan.org/pod/Zonemaster::Engine::Profile
+