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/utils/README.md

@@ -0,0 +1,73 @@
+# Document generation
+
+## Background
+
+The utility scripts described below are used to update or generate some documents
+in the public document tree.
+
+* The scripts should be run at each Zonemaster release and the resulting update
+  should be submitted to correct git branch of this git repository.
+
+## Pre-requisite
+
+The scripts should be run on a computer where the updated git branch of
+`zonemaster/zonemaster` has been cloned, and the equivalent version of
+`zonemaster/engine` has been **installed**. Usually the git branches will
+be the `develop` branches of each repository.
+
+## Scripts
+
+* [generateTestCaseList.pl]
+  * This tool extracts all Test Case specifications and creates a Markdown table
+    to be inserted in [Test Case README].
+* [updateTestPlanReadme.pl]
+  * This tool extracts all Test Case specifications per Test Plan and creates
+    Markdown tables. The tables are automatically added to the Test Plan
+    README.md file which is located in the directory named after the Test Plan.
+* [generateTestMessages.pl]
+  * This tools creates a map between the Zonemaster message tags from the
+    [Zonemaster-Engine] implementation of the Test Cases and the Test Case
+    specifications. This is used to create the complete [TestMessages.md] file.
+* [generateImplementedTestCases.pl]
+  * This tool creates a list of implemented test cases from the
+    [Zonemaster-Engine] implementation. This is used to create the complete
+    [ImplementedTestCases.md] file.
+    
+## Steps to be run
+
+1. You are assumed to start from the root of the zonemaster/zonemaster tree.
+   Go to directory to execute the commands from.
+```sh
+cd docs/public/specifications/tests
+```
+2. All commands below must be run from the directory you are in now.
+3. Remove Test Case table from [README.md][Test Case README] in that directory
+   and save the file.
+4. Run:
+```sh
+../../../../utils/generateTestCaseList.pl >> README.md
+```
+5. Run:
+```sh
+../../../../utils/updateTestPlanReadme.pl
+```
+6. Run:
+```sh
+../../../../utils/generateTestMessages.pl > TestMessages.md
+```
+7. Run:
+```sh
+../../../../utils/generateImplementedTestCases.pl > ImplementedTestCases.md
+```
+8. Verify any updated documents.
+9. Submit to git.
+
+
+[generateImplementedTestCases.pl]: generateImplementedTestCases.pl
+[generateTestCaseList.pl]:         generateTestCaseList.pl
+[generateTestMessages.pl]:         generateTestMessages.pl
+[ImplementedTestCases.md]:         ../docs/public/specifications/tests/ImplementedTestCases.md
+[Test Case README]:                ../docs/public/specifications/tests/README.md
+[TestMessages.md]:                 ../docs/public/specifications/tests/TestMessages.md
+[updateTestPlanReadme.pl]:         generateTestMessages.pl
+[Zonemaster-Engine]:               https://github.com/zonemaster/zonemaster-engine