功能：新增车辆违停和车辆拥堵检测算法

- IllegalParkingAlgorithm: 5状态机(IDLE→CONFIRMING_VEHICLE→PARKED_COUNTDOWN→ALARMED→CONFIRMING_CLEAR)
  禁停区域检测，15秒确认+5分钟倒计时，滑动窗口抗抖动，支持car/truck/bus/motorcycle
- VehicleCongestionAlgorithm: 4状态机(NORMAL→CONFIRMING_CONGESTION→CONGESTED→CONFIRMING_CLEAR)
  车辆计数≥阈值+持续60秒触发，滑动窗口平均值判断
- AlgorithmManager: 新增default_params、register_algorithm、get_status支持两种新算法
- main.py: 泛化alarm_id回填和first_frame_time提取，ext_data新增vehicle_count字段

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main.py

@@ -763,12 +763,16 @@ class EdgeInferenceService:
                 self._camera_alert_cooldown[dedup_key] = now
                 self._performance_stats["total_alerts_generated"] += 1
 
-                # 获取算法的离岗开始时间
-                leave_start_time = None
-                if alert_type == "leave_post":
-                    algo = self._algorithm_manager.algorithms.get(roi_id, {}).get(f"{roi_id}_{bind.bind_id}", {}).get("leave_post")
-                    if algo and hasattr(algo, '_leave_start_time') and algo._leave_start_time:
-                        leave_start_time = algo._leave_start_time.isoformat()
+                # 获取算法的事件开始时间（泛化：支持所有算法类型）
+                first_frame_time = None
+                algo = self._algorithm_manager.algorithms.get(roi_id, {}).get(f"{roi_id}_{bind.bind_id}", {}).get(alert_type)
+                if algo:
+                    # 各算法使用不同的内部变量名存储开始时间
+                    for attr in ('_leave_start_time', '_parking_start_time', '_congestion_start_time', '_intrusion_start_time'):
+                        val = getattr(algo, attr, None)
+                        if val:
+                            first_frame_time = val.isoformat()
+                            break
 
                 from core.result_reporter import AlarmInfo, generate_alarm_id
                 alarm_info = AlarmInfo(
@@ -788,20 +792,16 @@ class EdgeInferenceService:
                         "bind_id": bind.bind_id,
                         "message": alert.get("message", ""),
                         "edge_node_id": self._settings.mqtt.device_id,
-                        "first_frame_time": leave_start_time,
+                        "first_frame_time": first_frame_time,
+                        "vehicle_count": alert.get("vehicle_count"),
                     },
                 )
                 self._reporter.report_alarm(alarm_info, screenshot=frame.image)
 
-                # 回填 alarm_id 到算法实例（用于后续 resolve 追踪）
-                if alert_type == "leave_post":
-                    algo = self._algorithm_manager.algorithms.get(roi_id, {}).get(f"{roi_id}_{bind.bind_id}", {}).get("leave_post")
-                    if algo and hasattr(algo, 'set_last_alarm_id'):
-                        algo.set_last_alarm_id(alarm_info.alarm_id)
-                elif alert_type == "intrusion":
-                    algo = self._algorithm_manager.algorithms.get(roi_id, {}).get(f"{roi_id}_{bind.bind_id}", {}).get("intrusion")
-                    if algo and hasattr(algo, 'set_last_alarm_id'):
-                        algo.set_last_alarm_id(alarm_info.alarm_id)
+                # 回填 alarm_id 到算法实例（用于后续 resolve 追踪，泛化支持所有算法类型）
+                algo = self._algorithm_manager.algorithms.get(roi_id, {}).get(f"{roi_id}_{bind.bind_id}", {}).get(alert_type)
+                if algo and hasattr(algo, 'set_last_alarm_id'):
+                    algo.set_last_alarm_id(alarm_info.alarm_id)
 
                 self._logger.info(
                     f"告警已生成: type={alert_type}, "