curl --request POST \
  --url https://crypto.westminister.tech/api/v1/auth/files/upload \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form file='@example-file' \
  --form purpose=otc_bank_receipt

{
  "file_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "purpose": "<string>",
  "file_name": "<string>",
  "stored_name": "<string>",
  "content_type": "<string>",
  "size_bytes": 123,
  "uploaded_at": "2023-11-07T05:31:56Z",
  "file_url": "<string>"
}