查询任务结果

{
    "taskId": "task_20260511_abc123",
    "status": "completed",
    "url": "https://oss.xingluan.cn/result/video.mp4",
    "amount": 0.05,
    "cost": 0.00005,
    "usage": {
        "outputDuration": 5
    },
    "errMsg": null
}