feat: add BigQuery Python functions and BQClient type

Funciones CRUD completas para BigQuery: auth, datasets, tables, queries,
jobs, routines, load/export. Tipo BQClient como wrapper del SDK oficial.

python/functions/bigquery/bq_delete_routine.md

@@ -0,0 +1,51 @@
+---
+name: bq_delete_routine
+kind: function
+lang: py
+domain: infra
+version: "1.0.0"
+purity: impure
+signature: "def bq_delete_routine(client: BQClient, dataset_id: str, routine_id: str) -> None"
+description: "Elimina una routine de un dataset."
+tags: [bigquery, gcp, routine, udf, delete, google-cloud, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: true
+error_type: "error_go_core"
+imports: [google-cloud-bigquery]
+params:
+  - name: client
+    desc: "instancia autenticada de BQClient"
+  - name: dataset_id
+    desc: "nombre del dataset que contiene la routine"
+  - name: routine_id
+    desc: "nombre/identificador de la routine a eliminar"
+output: "None; lanza NotFound si la routine no existe"
+tested: false
+tests: []
+test_file_path: ""
+file_path: "python/functions/bigquery/routines.py"
+---
+
+## Ejemplo
+
+```python
+from bigquery.client import bq_auth
+from bigquery.routines import bq_delete_routine
+
+client = bq_auth("my-project")
+bq_delete_routine(client, "analytics", "double_value")
+# La routine queda eliminada permanentemente
+```
+
+## Notas
+
+Lanza `google.api_core.exceptions.NotFound` (404) si la routine no existe. La operacion es permanente e irreversible.
+
+Para eliminar y recrear una routine actualizada, combinar con `bq_create_routine`:
+
+```python
+bq_delete_routine(client, "analytics", "double_value")
+bq_create_routine(client, "analytics", "double_value", body="x * 3", ...)
+```