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_get_database.md

@@ -0,0 +1,33 @@
+---
+name: metabase_get_database
+kind: function
+lang: py
+domain: infra
+version: "1.0.0"
+purity: impure
+signature: "def metabase_get_database(client: MetabaseClient, database_id: int) -> dict"
+description: "Obtiene los detalles de una database de Metabase por su ID. Endpoint: GET /api/database/:id."
+tags: [metabase, database, get, api, python]
+uses_functions: []
+uses_types: [MetabaseClient_go_infra]
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: [httpx]
+tested: false
+tests: []
+test_file_path: ""
+file_path: "python/functions/metabase/databases.py"
+---
+
+## Ejemplo
+
+```python
+db = metabase_get_database(client, 2)
+print(db["name"], db["engine"])
+```
+
+## Notas
+
+Error 404 si la database no existe. Retorna campos completos incluyendo
+id, name, engine, details, is_full_sync, auto_run_queries, created_at, features.