curl --request GET \
  --url https://staging.cutmake.ai/api/v1/purchase-orders/fixed-cost/{document_id} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "internalId": "<string>",
  "status": "<string>",
  "currentVersion": 123,
  "purpose": "<string>",
  "expenseCategory": "<string>",
  "frequency": "<string>",
  "currency": "<string>",
  "subtotal": "<string>",
  "taxRate": "<string>",
  "taxAmount": "<string>",
  "total": "<string>",
  "createdAt": "<string>",
  "createdBy": "<string>",
  "vendorId": "<string>",
  "vendorName": "<string>",
  "employeeId": "<string>",
  "employeeName": "<string>",
  "referenceNumber": "<string>",
  "internalNotes": "<string>",
  "items": []
}