curl --request POST \
  --url https://api.ai2fin.com/api/transaction-categories/{transactionId} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "categoryId": "<string>",
  "categorySetId": "<string>",
  "isPrimary": false,
  "confidence": 0.5,
  "notes": "<string>"
}
'

{
  "success": true,
  "category": {
    "id": "<string>",
    "transactionId": "<string>",
    "categoryId": "<string>",
    "categorySetId": "<string>",
    "userId": "<string>",
    "isPrimary": true,
    "confidence": 0.5,
    "assignedAt": "2023-11-07T05:31:56Z",
    "notes": "<string>",
    "category": {
      "id": "<string>",
      "name": "<string>",
      "icon": "<string>",
      "color": "<string>",
      "isTaxDeductible": true,
      "taxCategory": "<string>",
      "defaultGstRate": 123
    }
  }
}