curl --request GET \
  --url https://api.zangsho.com/v1/customers/{customerIdOrExternalId} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": 123,
    "email": "<string>",
    "name": "<string>",
    "phone": "<string>",
    "external_id": "<string>",
    "metadata": {},
    "ltv": "29800.00",
    "order_count": 123,
    "first_payment_at": "2023-11-07T05:31:56Z",
    "last_payment_at": "2023-11-07T05:31:56Z",
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z"
  }
}