add: fileObject purpose type

[ghdcksgml1]

• I understand that this repository is auto-generated and my pull request may not be merged

Changes being requested

Fixed missing user_data purpose type in the FileObject interface to match the official OpenAI API specification.

Changes:

• Added 'user_data' to the union type definition for the purpose field
• Updated JSDoc comment to include user_data in the supported values list

Additional context & links

According to the OpenAI Files API documentation, user_data is a valid purpose value that can be used when uploading files. However, this option was missing from the TypeScript interface definition, causing a mismatch between the actual API capabilities and the type definitions.

The user_data purpose is commonly used for general file uploads (as seen in OpenAI's web dashboard) and is referenced in community discussions about file purposes, but was inadvertently omitted from this generated interface.

Example

curl https://api.openai.com/v1/files \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -F purpose="user_data" \
  -F file="@my.pdf"

// response
{
  "id": "file-abc123",
  "object": "file",
  "bytes": 120000,
  "created_at": 1677610602,
  "filename": "my.pdf",
  "purpose": "user_data",
}