Fetch contract

curl --request GET \
  --url https://api.useaira.com/v1/contracts/{id} \
  --header 'X-API-KEY: <api-key>'

{
  "contract": {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "startDate": "2023-12-25",
    "endDate": "2023-12-25",
    "billingEndDay": 16,
    "status": "active",
    "plans": [
      {
        "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "name": "<string>",
        "description": "<string>"
      }
    ],
    "paymentSettings": {
      "scheduledPaymentDay": 16,
      "dueOffsetDays": 6
    },
    "billingSettings": {
      "billingCycleMinimumAmount": 1
    },
    "customFields": {}
  },
  "customer": {
    "id": "<string>",
    "externalId": "cust_1234567890abcdef",
    "name": "Acme Inc.",
    "customFields": {
      "custom_field_1": "value1",
      "custom_field_2": "value2"
    }
  },
  "paymentAccount": {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "businessName": "<string>",
    "tradeName": "<string>",
    "taxId": "<string>",
    "email": "jsmith@example.com",
    "address": {
      "zipCode": "<string>",
      "number": "<string>",
      "street": "<string>",
      "neighborhood": "<string>",
      "city": "<string>",
      "state": "AC",
      "country": "Brasil",
      "complement": "<string>"
    }
  }
}