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

{
  "id": "file_abc123",
  "object": "file",
  "bytes": 120000,
  "created_at": 1677610602,
  "filename": "document.pdf",
  "purpose": "assistants",
  "status": "processed"
}