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)

algorithms.py

@@ -47,6 +47,9 @@ class LeavePostAlgorithm:
         self.alarm_sent: bool = False
         self.last_person_time: Optional[datetime] = None
 
+        self._last_alarm_id: Optional[str] = None      # 最近一次告警ID
+        self._leave_start_time: Optional[datetime] = None  # 离岗开始时间（LEAVING 状态的开始时间）
+
     def _is_in_working_hours(self, dt: Optional[datetime] = None) -> bool:
         if not self.working_hours:
             return True
@@ -123,15 +126,28 @@ class LeavePostAlgorithm:
         alerts = []
 
         if not in_work:
+            if self.state == self.STATE_OFF_DUTY and self._last_alarm_id and self._leave_start_time:
+                duration_ms = int((current_time - self._leave_start_time).total_seconds() * 1000)
+                alerts.append({
+                    "alert_type": "alarm_resolve",
+                    "resolve_alarm_id": self._last_alarm_id,
+                    "duration_ms": duration_ms,
+                    "last_frame_time": current_time.isoformat(),
+                    "resolve_type": "non_work_time",
+                })
+                self._last_alarm_id = None
+                self._leave_start_time = None
             self.state = self.STATE_NON_WORK_TIME
             self.detection_history.clear()
             self.alarm_sent = False
-            return []
+            return alerts
 
         if self.state == self.STATE_NON_WORK_TIME:
             self.state = self.STATE_WAITING
+            self.state_start_time = None
             self.detection_history.clear()
             self.alarm_sent = False
+            self.alert_cooldowns.clear()  # 新工作时段，清除冷却记录
 
         roi_has_person = False
         for det in tracks:
@@ -162,6 +178,8 @@ class LeavePostAlgorithm:
                     # 持续在岗达到确认时长，正式确认上岗
                     self.state = self.STATE_ON_DUTY
                     self.state_start_time = current_time
+                    # 确认在岗后清除冷却记录，允许新一轮离岗检测告警
+                    self.alert_cooldowns.clear()
 
         elif self.state == self.STATE_ON_DUTY:
             self.detection_history.append((current_time, roi_has_person))
@@ -178,6 +196,7 @@ class LeavePostAlgorithm:
                 self.state_start_time = current_time
             elif elapsed >= self.confirm_leave_sec:
                 # 确认离岗后直接触发告警，不再进入 OFF_DUTY 二次等待
+                leaving_start_time = self.state_start_time  # 保存 LEAVING 状态开始时间（人员离开时间）
                 self.state = self.STATE_OFF_DUTY
                 self.state_start_time = current_time
 
@@ -196,30 +215,37 @@ class LeavePostAlgorithm:
                     })
                     self.alert_cooldowns[cooldown_key] = now
 
+                    # 保存告警追踪信息（alarm_id 由 main.py 通过 set_last_alarm_id() 回填）
+                    self._last_alarm_id = None
+                    self._leave_start_time = leaving_start_time  # LEAVING 状态开始时间 = 人员离开时间
+
         elif self.state == self.STATE_OFF_DUTY:
-            # OFF_DUTY 状态：等待人员回岗或冷却后可再次告警
+            # OFF_DUTY 状态：只等待人员回岗，不再重复告警
+            # 必须经过 CONFIRMING 重新确认在岗后，才允许新一轮离岗检测
             if roi_has_person:
-                self.state = self.STATE_ON_DUTY
-                self.state_start_time = current_time
-            else:
-                elapsed = (current_time - self.state_start_time).total_seconds()
-                cooldown_key = f"{camera_id}_{roi_id}"
-                now = datetime.now()
-                if cooldown_key in self.alert_cooldowns and (now - self.alert_cooldowns[cooldown_key]).total_seconds() > self.cooldown_sec:
-                    bbox = self._get_latest_bbox(tracks, roi_id)
-                    elapsed_minutes = int(elapsed / 60)
+                # 生成 resolve 事件（人员回岗）
+                if self._last_alarm_id and self._leave_start_time:
+                    duration_ms = int((current_time - self._leave_start_time).total_seconds() * 1000)
                     alerts.append({
-                        "track_id": roi_id,
-                        "camera_id": camera_id,
-                        "bbox": bbox,
-                        "duration_minutes": elapsed_minutes,
-                        "alert_type": "leave_post",
-                        "message": f"持续离岗 {elapsed_minutes} 分钟",
+                        "alert_type": "alarm_resolve",
+                        "resolve_alarm_id": self._last_alarm_id,
+                        "duration_ms": duration_ms,
+                        "last_frame_time": current_time.isoformat(),
+                        "resolve_type": "person_returned",
                     })
-                    self.alert_cooldowns[cooldown_key] = now
+                self._last_alarm_id = None
+                self._leave_start_time = None
+                self.state = self.STATE_CONFIRMING
+                self.state_start_time = current_time
+                self.detection_history.clear()
+                self.detection_history.append((current_time, True))
 
         return alerts
 
+    def set_last_alarm_id(self, alarm_id: str):
+        """由 main.py 在告警生成后回填 alarm_id"""
+        self._last_alarm_id = alarm_id
+
     def reset(self):
         self.state = self.STATE_WAITING
         self.state_start_time = None
@@ -227,6 +253,8 @@ class LeavePostAlgorithm:
         self.alarm_sent = False
         self.last_person_time = None
         self.alert_cooldowns.clear()
+        self._last_alarm_id = None
+        self._leave_start_time = None
 
     def get_state(self, roi_id: str) -> Dict[str, Any]:
         return {