获取文档列表

{
    "documents": [
        {
            "document_id": 0,
            "filename": "string",
            "file_type": "string",
            "file_size": 0,
            "status": "pending",
            "chunk_count": 0,
            "error_message": null,
            "is_selected": false,
            "created_at": "string",
            "updated_at": "string"
        }
    ],
    "total": 0
}