curl --request PATCH \
  --url https://brew.new/api/contacts \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "email": "john@example.com",
  "firstName": "Johnny",
  "customFields": {
    "company": "Acme Corp",
    "department": "Engineering"
  }
}
'

{
  "success": true,
  "data": {
    "email": "jsmith@example.com",
    "firstName": "<string>",
    "lastName": "<string>",
    "subscribed": true,
    "customFields": {},
    "createdAt": 123,
    "updatedAt": 123
  },
  "meta": {
    "requestId": "<string>"
  }
}