curl -X GET \
  'https://api.appcharge.com/coupons/coupon/summer26/promo-code/swx1' \
  -H 'x-publisher-token: <x-publisher-token>'

{
    "name": "swx1",
    "active": true,
    "maxRedemptions": 250,
    "createdAt": "2025-01-22T15:58:24.116Z",
    "updatedAt": "2025-01-25T08:44:26.668Z",
    "redemptions": 100,
}

{
    "error": "Invalid coupon name. Use only English letters and numbers."
}

{
    "error": "Invalid promo code name. Use only English letters and numbers."
}

{
    "error": "Coupon not found."
}

{
    "error": "Promo code not found."
}

{
    "error": "Unexpected error. Please contact support."
}