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-backend/docs/TypographicConventions.md

@@ -0,0 +1,28 @@
+# Typographic conventions
+
+The Zonemaster Backend documentation uses the following typographic conventions:
+
+*Italic* text is used for:
+
+* technical terms defined in the [Architecture] document
+* data types defined in the [API] document
+
+`Monospace` text is used for:
+
+* snippets of JSON or sh
+* JSON-RPC method names
+* JSON values
+* single or strings of characters
+* internet addresses (e.g. domain names and IP addresses)
+* file names with or without paths (e.g. configuration files and command line
+  tools)
+* config section names
+
+>
+> Block quotes are used for:
+>
+> * notes and commentary
+>
+
+[API]:          https://github.com/zonemaster/zonemaster/blob/master/docs/public/using/backend/rpcapi-reference.md
+[Architecture]: Architecture.md