feat(aiot): 离岗检测重写 - 单次告警 + 回岗确认 + 持续时长追踪

算法逻辑修改：
- OFF_DUTY状态只告警一次，不再每600秒重复告警
- 人员回岗后需经CONFIRMING(10秒)重新确认才恢复ON_DUTY
- 确认在岗后清除冷却记录，允许新一轮离岗检测
- 非工作时间进入时清除冷却记录

持续时长追踪（新增resolve机制）：
- 离岗告警记录alarm_id和leave_start_time
- 人员回岗确认后生成resolve事件(duration_ms + last_frame_time)
- 进入非工作时间时也生成resolve事件
- ResultReporter新增report_alarm_resolve()写入Redis队列
- AlarmUploadWorker新增_process_resolve() HTTP POST到云端
- main.py区分普通告警和resolve事件，回填alarm_id到算法实例
- 告警ext_data附加first_frame_time(离岗开始时间)

core/alarm_upload_worker.py

@@ -173,6 +173,11 @@ class AlarmUploadWorker:
             self._logger.error(f"告警 JSON 解析失败: {e}")
             return
 
+        # 如果是 resolve 事件，走单独的处理逻辑
+        if alarm_data.get("_type") == "resolve":
+            self._process_resolve(alarm_data)
+            return
+
         alarm_id = alarm_data.get("alarm_id", "unknown")
         retry_count = alarm_data.get("_retry_count", 0)
 
@@ -241,6 +246,36 @@ class AlarmUploadWorker:
             # HTTP 上报失败，进入重试
             self._handle_retry(alarm_json, "HTTP 上报失败")
 
+    def _process_resolve(self, resolve_data: dict):
+        """处理告警结束事件 - HTTP POST 到云端"""
+        upload_cfg = self._settings.alarm_upload
+        base_url = upload_cfg.cloud_api_url.rstrip("/")
+        url = f"{base_url}/admin-api/aiot/alarm/edge/resolve"
+
+        headers = {"Content-Type": "application/json"}
+        if upload_cfg.edge_token:
+            headers["Authorization"] = f"Bearer {upload_cfg.edge_token}"
+
+        payload = {
+            "alarm_id": resolve_data.get("alarm_id"),
+            "duration_ms": resolve_data.get("duration_ms"),
+            "last_frame_time": resolve_data.get("last_frame_time"),
+            "resolve_type": resolve_data.get("resolve_type"),
+        }
+
+        try:
+            response = requests.post(url, json=payload, headers=headers, timeout=10)
+            if response.status_code == 200:
+                body = response.json()
+                if body.get("code") == 0:
+                    self._logger.info(f"告警结束上报成功: {resolve_data.get('alarm_id')}")
+                else:
+                    self._logger.warning(f"告警结束上报业务错误: {body}")
+            else:
+                self._logger.warning(f"告警结束上报失败: status={response.status_code}")
+        except Exception as e:
+            self._logger.warning(f"告警结束上报异常: {e}")
+
     def _upload_snapshot_to_cos(
         self, local_path: str, alarm_id: str, device_id: str
     ) -> Optional[str]: