SMS 배치 상태 조회

curl --request GET \
  --url https://client-api.tryvox.co/v3/sms/batch/{batch_id} \
  --header 'Authorization: Bearer <token>'

{
  "batch_id": "<string>",
  "total_count": 1,
  "success_count": 1,
  "failure_count": 1,
  "pending_count": 1,
  "created_at": 123,
  "items": [
    {
      "index": 1,
      "to_number": "<string>",
      "sms_message_id": "<string>",
      "error": {
        "code": "<string>",
        "message": "<string>",
        "details": {}
      },
      "metadata": {}
    }
  ],
  "title": "<string>",
  "finished_at": 123
}