feat(metabase): nuevos modulos — snippets, notifications, dashboard_filters

Tres modulos nuevos con funciones CRUD completas:
- snippets: list, get, create, update, archive (SQL reutilizable)
- notifications: list, create_card_alert, create_dashboard_subscription, update, delete
- dashboard_filters: add_dashboard_filter (parameter_mappings sobre cards existentes)

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

python/functions/metabase/metabase_create_dashboard_subscription.md

@@ -0,0 +1,53 @@
+---
+name: metabase_create_dashboard_subscription
+kind: function
+lang: py
+domain: infra
+version: "1.0.0"
+purity: impure
+signature: "def metabase_create_dashboard_subscription(client: MetabaseClient, dashboard_id: int, cron_schedule: str, recipients: list[dict]) -> dict"
+description: "Crea una suscripcion periodica a un dashboard de Metabase. Envia el dashboard completo por email segun el cron configurado. Endpoint: POST /api/notification."
+tags: [metabase, notification, subscription, dashboard, create, api, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: []
+params:
+  - name: client
+    desc: "instancia autenticada de MetabaseClient"
+  - name: dashboard_id
+    desc: "ID del dashboard a enviar periodicamente"
+  - name: cron_schedule
+    desc: "expresion cron de 5 campos (ej: '0 8 * * 1-5' = lun-vie 8am, '0 9 * * 1' = lunes 9am)"
+  - name: recipients
+    desc: "lista de destinatarios: usuario Metabase {'type': 'notification-recipient/user', 'user_id': N} o email externo {'type': 'notification-recipient/raw-value', 'details': {'email': 'x@y.com'}}"
+output: "dict: suscripcion creada con id, active, payload_type, payload, subscriptions, handlers, created_at"
+tested: false
+tests: []
+test_file_path: ""
+file_path: "python/functions/metabase/notifications.py"
+---
+
+## Ejemplo
+
+```python
+# Suscripcion: enviar dashboard de ventas cada lunes a las 8am
+sub = metabase_create_dashboard_subscription(
+    client,
+    dashboard_id=42,
+    cron_schedule="0 8 * * 1",
+    recipients=[
+        {"type": "notification-recipient/user", "user_id": 5},
+        {"type": "notification-recipient/raw-value", "details": {"email": "gerencia@aurgi.com"}},
+    ],
+)
+print(sub["id"], sub["payload"]["dashboard_id"])
+```
+
+## Notas
+
+Requiere Metabase 0.57+. Reemplaza el antiguo /api/pulse.
+El dashboard se envia completo con todas sus cards renderizadas.
+Para suscripciones diarias laborales usar cron "0 8 * * 1-5".