feat: 围栏Tab布局重构、低精度过滤、蓝牙考勤去重、考勤删除API

- 围栏管理页面Tab移至顶部，设备绑定Tab隐藏地图全屏展示绑定矩阵
- 位置追踪新增"低精度"按钮，隐藏LBS/WiFi点(地图+折线+表格联动)
- 移除LBS/WiFi精度半径圆圈，仅通过标记颜色区分定位类型
- 蓝牙打卡(0xB2)自动创建考勤记录，含去重和WebSocket广播
- 新增考勤批量删除和单条删除API
- fence_checker补充json导入

via [HAPI](https://hapi.run)

Co-Authored-By: HAPI <noreply@hapi.run>

app/services/fence_checker.py

@@ -4,6 +4,7 @@ Checks whether a device's reported coordinates fall inside its bound fences.
 Creates automatic attendance records (clock_in/clock_out) on state transitions.
 """
 
+import json
 import logging
 import math
 from datetime import datetime, timedelta, timezone