ProcessResultResponseDto

{
    "id": "507f1f77bcf86cd799439011",
    "type": "leads_export",
    "status": "pending",
    "result": {
        "s3_key": "exports/abc12345/csv_export_1736172000.csv",
        "s3_url": "https://...",
        "file_size": 2048576,
        "format": "csv",
        "encoding": "utf8",
        "duration_ms": 15420
    }
}