feat(aiot): 数据库schema更新 - 添加离岗倒计时参数

问题描述：
- 离岗检测算法param_schema缺少leave_countdown_sec参数
- 部分默认值不符合业务需求

修改内容：
1. 初始化-mysql-aiot.sql (Line 76)
   - leave_post算法新增参数：
     "leave_countdown_sec": {"type":"int","default":300,"min":0}
   - 修正默认值：
     confirm_leave_sec: 10 → 30秒
     cooldown_sec: 300 → 600秒

2. 新增迁移脚本：迁移-添加离岗倒计时参数.sql
   - UPDATE wvp_ai_algorithm表的param_schema
   - 适用于已部署的生产环境数据库升级

参数说明：
- confirm_on_duty_sec: 上岗确认期（默认10秒）
- confirm_leave_sec: 离岗确认期（默认30秒）
- leave_countdown_sec: 离岗倒计时（默认300秒=5分钟）
- cooldown_sec: 告警冷却期（默认600秒=10分钟）

业务流程：
人离开 → 30s确认离岗 → 300s倒计时 → 触发告警

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

数据库/aiot/初始化-mysql-aiot.sql

@@ -73,5 +73,5 @@ CREATE TABLE IF NOT EXISTS wvp_ai_config_log (
 -- 初始数据：预置算法（2个，与边缘端保持一致）
 -- ============================================================
 INSERT INTO wvp_ai_algorithm (algo_code, algo_name, target_class, param_schema, description, is_active, create_time, update_time) VALUES
-('leave_post', '离岗检测', 'person', '{"confirm_on_duty_sec":{"type":"int","default":10,"min":1},"confirm_leave_sec":{"type":"int","default":10,"min":1},"cooldown_sec":{"type":"int","default":300,"min":0},"working_hours":{"type":"list","default":[]}}', '检测人员是否在岗，支持工作时间段配置', 1, NOW(), NOW()),
+('leave_post', '离岗检测', 'person', '{"confirm_on_duty_sec":{"type":"int","default":10,"min":1},"confirm_leave_sec":{"type":"int","default":30,"min":1},"leave_countdown_sec":{"type":"int","default":300,"min":0},"cooldown_sec":{"type":"int","default":600,"min":0},"working_hours":{"type":"list","default":[]}}', '检测人员是否在岗，支持工作时间段配置', 1, NOW(), NOW()),
 ('intrusion', '周界入侵检测', 'person', '{"cooldown_seconds":{"type":"int","default":120,"min":0},"confirm_seconds":{"type":"int","default":5,"min":1}}', '检测人员进入指定区域', 1, NOW(), NOW());

数据库/aiot/迁移-添加离岗倒计时参数.sql

@@ -0,0 +1,19 @@
+-- ============================================================
+-- AIoT 离岗检测算法参数更新迁移脚本
+-- 功能：添加 leave_countdown_sec（离岗倒计时）参数
+-- 执行时间：2026-02-12
+-- ============================================================
+
+-- 更新 leave_post 算法的 param_schema
+-- 添加 leave_countdown_sec (默认300秒 = 5分钟)
+-- 修正 confirm_leave_sec 默认值从10秒改为30秒
+-- 修正 cooldown_sec 默认值从300秒改为600秒
+UPDATE wvp_ai_algorithm
+SET param_schema = '{"confirm_on_duty_sec":{"type":"int","default":10,"min":1},"confirm_leave_sec":{"type":"int","default":30,"min":1},"leave_countdown_sec":{"type":"int","default":300,"min":0},"cooldown_sec":{"type":"int","default":600,"min":0},"working_hours":{"type":"list","default":[]}}',
+    update_time = NOW()
+WHERE algo_code = 'leave_post';
+
+-- 验证更新结果
+SELECT algo_code, algo_name, param_schema, update_time
+FROM wvp_ai_algorithm
+WHERE algo_code = 'leave_post';