Reject affiliate application

curl --request POST \
  --url https://api.shoppex.io/dev/v1/affiliates/applications/{id}/reject \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "application": {
      "id": "app_1",
      "customer_id": "cus_2",
      "status": "rejected",
      "code": "pending-creator",
      "url": "https://demo.shoppex.io?via=pending-creator",
      "updated_at": "2026-03-15T12:00:00.000Z"
    }
  }
}