curl --request GET \
  --url https://demo.spreecommerce.org/api/v2/storefront/account/credit_cards/default \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": "1",
    "type": "credit_card",
    "attributes": {
      "cc_type": "visa",
      "last_digits": "4111",
      "month": 12,
      "year": 2026,
      "name": "John Doe",
      "default": true,
      "gateway_payment_profile_id": "card_1JqvNB2eZvKYlo2C5OlqLV7S"
    },
    "relationships": {
      "payment_method": {
        "data": {
          "id": "1",
          "type": "payment_method"
        }
      }
    }
  },
  "included": [
    {
      "id": "1",
      "type": "payment_method",
      "attributes": {
        "type": "Spree::Gateway::StripeGateway",
        "name": "Stripe",
        "description": "Stripe Payments",
        "preferences": {}
      }
    }
  ]
}