List coupons

Example response

{
  "data": [
    {
      "id": "clx1234567890",
      "code": "SUMMER2026",
      "name": "Summer Sale",
      "description": "20% off all plans",
      "discountType": "PERCENTAGE",
      "discountValue": "20.0000",
      "currency": "USD",
      "maxRedemptions": 100,
      "redemptionCount": 5,
      "appliesToPlanIds": [
        "clxplan123"
      ],
      "isActive": true
    }
  ],
  "meta": {
    "total": 150,
    "page": 1,
    "limit": 20,
    "totalPages": 8
  }
}