curl --request POST \
  --url https://app.aigmented.com/api/v1/collections/{id}/files/upload \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form file='@example-file'

{
  "file_id": 42,
  "filename": "contract-2024.pdf",
  "status": "processing",
  "content_type": "application/pdf",
  "size_bytes": 1048576
}