curl --request POST \
  --url https://cloud.onyx.app/api/user/projects/file/upload \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'files=<string>' \
  --form project_id=123 \
  --form 'temp_id_map=<string>' \
  --form files.items='@example-file'

{
  "user_files": [
    {
      "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "name": "<string>",
      "user_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "file_id": "<string>",
      "created_at": "2023-11-07T05:31:56Z",
      "last_accessed_at": "2023-11-07T05:31:56Z",
      "file_type": "<string>",
      "token_count": 123,
      "chunk_count": 123,
      "temp_id": "<string>",
      "project_id": 123
    }
  ],
  "rejected_files": [
    {
      "file_name": "<string>",
      "reason": "<string>"
    }
  ]
}