List house discounts

{
  "items": [
    {
      "id": "17",
      "storefrontId": "1234",
      "houseDomain": "nike.com",
      "scope": "brand",
      "discountPercent": 12,
      "notes": "Negotiated 2026 Nike-house rate.",
      "createdAt": "2026-06-27T15:00:00.000Z",
      "updatedAt": "2026-06-27T15:00:00.000Z",
      "createdBy": "operator@touchline.example"
    }
  ],
  "total": 1
}