curl --request POST \
  --url https://api.minimaxi.com/v1/files/upload \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form purpose=prompt_audio \
  --form file=@example-file

{
  "file": {
    "file_id": "${file_id}",
    "bytes": 5896337,
    "created_at": 1700469398,
    "filename": "sample.mp3",
    "purpose": "prompt_audio"
  },
  "base_resp": {
    "status_code": 0,
    "status_msg": "success"
  }
}