curl --request POST \
  --url https://api.artu.ai/clients/{id}/migrate/preview \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'X-Environment: <api-key>' \
  --data '
{
  "precedence": "source",
  "include": {
    "addresses": true,
    "bankAccounts": true,
    "contactMethods": true,
    "documents": true,
    "relationships": true,
    "transactions": true
  }
}
'

{
  "target": {
    "exists": true,
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
  },
  "blockers": [
    {
      "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "label": "<string>",
      "reason": "<unknown>"
    }
  ],
  "items": [
    {
      "total": 4503599627370495,
      "creates": 4503599627370495,
      "updates": 4503599627370495
    }
  ]
}