feat: 新增人员徘徊/静止行为分析功能

本次提交实现了完整的人员行为分析系统，包括：
1. 新增基于位置和跟踪ID的两种行为检测算法
2. 新增徘徊检测服务与行为处理器模块
3. 前后端集成算法配置界面与告警展示
4. 支持图片和视频流场景下的行为分析
5. 新增算法配置接口与文档说明

具体改动：
- 新增loitering_detection模型目录与算法实现
- 新增AlgorithmConfig组件实现可视化配置
- 扩展图片/视频检测接口支持算法参数传递
- 新增行为告警推送与前端展示页面
- 优化检测服务，集成行为分析逻辑
- 移除冗余日志输出，完善代码注释

apps/server/services/loitering_service.py

@@ -0,0 +1,168 @@
+"""
+徘徊检测服务
+集成行为检测算法到后端服务
+"""
+
+import sys
+import os
+from typing import Dict, List, Optional
+import logging
+
+# 添加算法模块路径
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..', '..', 'models', 'loitering_detection'))
+
+from processors import BehaviorProcessor
+
+logger = logging.getLogger(__name__)
+
+
+class LoiteringService:
+    """
+    徘徊检测服务
+    
+    为视频流检测提供行为分析功能：
+    - 静止检测（基于位置，无需跟踪）
+    - 徘徊检测（基于跟踪ID）
+    """
+    
+    def __init__(self):
+        self.processor = None
+        self.is_initialized = False
+    
+    def initialize(
+        self,
+        stationary_threshold: float = 10.0,
+        position_tolerance: int = 50,
+        loitering_threshold: float = 300.0,
+        movement_threshold: float = 5.0,
+        enable_stationary_alert: bool = True,
+        enable_loitering_alert: bool = True,
+        stationary_alert_threshold: Optional[float] = None,
+        loitering_alert_threshold: Optional[float] = None
+    ):
+        """
+        初始化服务
+
+        Args:
+            stationary_threshold: 静止检测阈值（秒）- 用于判断是否静止
+            position_tolerance: 位置容差（像素）
+            loitering_threshold: 徘徊检测阈值（秒）- 用于判断是否徘徊
+            movement_threshold: 移动阈值（像素）
+            enable_stationary_alert: 是否启用静止告警
+            enable_loitering_alert: 是否启用徘徊告警
+            stationary_alert_threshold: 静止告警阈值（秒）- 超过此时间产生告警，默认等于 stationary_threshold
+            loitering_alert_threshold: 徘徊告警阈值（秒）- 超过此时间产生告警，默认等于 loitering_threshold
+        """
+        try:
+            self.processor = BehaviorProcessor(
+                stationary_threshold=stationary_threshold,
+                position_tolerance=position_tolerance,
+                loitering_threshold=loitering_threshold,
+                movement_threshold=movement_threshold,
+                enable_stationary_alert=enable_stationary_alert,
+                enable_loitering_alert=enable_loitering_alert,
+                stationary_alert_threshold=stationary_alert_threshold if stationary_alert_threshold is not None else stationary_threshold,
+                loitering_alert_threshold=loitering_alert_threshold if loitering_alert_threshold is not None else loitering_threshold
+            )
+            self.is_initialized = True
+            logger.info(f"徘徊检测服务初始化成功: 静止阈值={stationary_threshold}s, 告警阈值={stationary_alert_threshold or stationary_threshold}s")
+        except Exception as e:
+            logger.error(f"徘徊检测服务初始化失败: {e}")
+            self.is_initialized = False
+    
+    def process_detections(
+        self,
+        detections: List[Dict],
+        use_tracking: bool = False,
+        track_id_key: str = 'track_id'
+    ) -> Dict:
+        """
+        处理检测结果
+        
+        Args:
+            detections: YOLO检测结果列表
+            use_tracking: 是否使用跟踪ID
+            track_id_key: 跟踪ID字段名
+        
+        Returns:
+            {
+                'detections': 添加行为信息的检测结果,
+                'alerts': 触发的告警列表,
+                'stats': 统计信息
+            }
+        """
+        if not self.is_initialized or not self.processor:
+            return {
+                'detections': detections,
+                'alerts': [],
+                'stats': {'error': '服务未初始化'}
+            }
+        
+        try:
+            return self.processor.process(
+                detections=detections,
+                use_tracking=use_tracking,
+                track_id_key=track_id_key
+            )
+        except Exception as e:
+            logger.error(f"处理检测结果失败: {e}")
+            return {
+                'detections': detections,
+                'alerts': [],
+                'stats': {'error': str(e)}
+            }
+    
+    def get_stationary_persons(self) -> List[Dict]:
+        """获取所有静止人员"""
+        if not self.is_initialized or not self.processor:
+            return []
+        return self.processor.get_stationary_persons()
+    
+    def get_loitering_persons(self) -> List[Dict]:
+        """获取所有徘徊人员"""
+        if not self.is_initialized or not self.processor:
+            return []
+        return self.processor.get_loitering_persons()
+    
+    def reset(self):
+        """重置检测器"""
+        if self.processor:
+            self.processor.reset()
+            logger.info("徘徊检测器已重置")
+    
+    def get_config(self) -> Dict:
+        """获取当前配置"""
+        if not self.is_initialized or not self.processor:
+            return {'error': '服务未初始化'}
+        return self.processor.get_config()
+    
+    def get_stats(self) -> Dict:
+        """获取统计信息"""
+        if not self.is_initialized or not self.processor:
+            return {'error': '服务未初始化'}
+        
+        stats = {
+            'stationary_count': len(self.get_stationary_persons()),
+            'loitering_count': len(self.get_loitering_persons()),
+            'config': self.get_config()
+        }
+        return stats
+
+
+# 全局服务实例
+_loitering_service: Optional[LoiteringService] = None
+
+
+def get_loitering_service() -> LoiteringService:
+    """获取全局徘徊检测服务实例"""
+    global _loitering_service
+    if _loitering_service is None:
+        _loitering_service = LoiteringService()
+    return _loitering_service
+
+
+def initialize_loitering_service(**kwargs):
+    """初始化全局徘徊检测服务"""
+    service = get_loitering_service()
+    service.initialize(**kwargs)
+    return service