feat: metabase_setup Python, fix list_databases, volumen Docker en init_metabase

Nueva función metabase_setup para setup inicial via API. Fix list_databases
que no extraía data del response wrapper. Pipeline init_metabase soporta
--mb-volumes para montar SQLite como volumen con fix de permisos automático.
Añadido .env a gitignore.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

python/functions/metabase/metabase_setup.md

@@ -0,0 +1,44 @@
+---
+name: metabase_setup
+kind: function
+lang: py
+domain: infra
+version: "1.0.0"
+purity: impure
+signature: "metabase_setup(base_url: str, admin_email: str, admin_password: str, admin_first_name: str, admin_last_name: str, site_name: str, site_locale: str) -> dict"
+description: "Ejecuta el setup inicial de una instancia Metabase nueva via POST /api/setup. Obtiene el setup-token automaticamente y crea el usuario admin con preferencias del sitio."
+tags: [metabase, setup, api, infra]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: [httpx]
+tested: false
+tests: []
+test_file_path: ""
+file_path: "python/functions/metabase/setup.py"
+---
+
+## Ejemplo
+
+```python
+from metabase.setup import metabase_setup
+
+result = metabase_setup(
+    base_url="http://localhost:3000",
+    admin_email="admin@fnregistry.local",
+    admin_password="FnRegistry2024!",
+    admin_first_name="Lucas",
+    admin_last_name="Admin",
+    site_name="fn-registry",
+    site_locale="es",
+)
+print(result["id"])  # session token
+```
+
+## Notas
+
+Solo funciona en instancias sin configurar (setup-token disponible). Si Metabase ya tiene un usuario, lanza RuntimeError.
+
+El setup-token se obtiene automaticamente de GET /api/session/properties. Una vez usado, Metabase invalida el token.