feat: 13个统计/聚合API + 前端同步 + 待完成功能文档

API新增:
- GET /api/system/overview 系统总览(在线率/今日统计/表大小)
- GET /api/locations/stats 位置统计(类型分布/小时趋势)
- GET /api/locations/track-summary/{id} 轨迹摘要(距离/时长/速度)
- POST /api/alarms/batch-acknowledge 批量确认告警
- GET /api/attendance/report 考勤日报表(每设备每天汇总)
- GET /api/bluetooth/stats 蓝牙统计(类型/TOP信标/RSSI分布)
- GET /api/heartbeats/stats 心跳统计(活跃设备/电量/间隔分析)
- GET /api/fences/stats 围栏统计(绑定/进出状态/今日事件)
- GET /api/fences/{id}/events 围栏进出事件历史
- GET /api/commands/stats 指令统计(成功率/类型/趋势)

API增强:
- devices/stats: 新增by_type/battery_distribution/signal_distribution
- alarms/stats: 新增today/by_source/daily_trend/top_devices
- attendance/stats: 新增today/by_source/daily_trend/by_device

前端同步:
- 仪表盘: 今日告警/考勤/定位卡片 + 在线率
- 告警页: 批量确认按钮 + 今日计数
- 考勤页: 今日计数
- 轨迹: 加载后显示距离/时长/速度摘要
- 蓝牙/围栏/指令页: 统计面板

文档: CLAUDE.md待完成功能按优先级重新规划

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

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

app/routers/bluetooth.py

@@ -86,6 +86,75 @@ async def list_bluetooth_records(
     )
 
 
+@router.get(
+    "/stats",
+    response_model=APIResponse[dict],
+    summary="蓝牙数据统计 / Bluetooth statistics",
+)
+async def bluetooth_stats(
+    start_time: datetime | None = Query(default=None, description="开始时间"),
+    end_time: datetime | None = Query(default=None, description="结束时间"),
+    db: AsyncSession = Depends(get_db),
+):
+    """
+    蓝牙数据统计：总记录数、按类型分布、按信标MAC分组TOP20、RSSI分布。
+    Bluetooth stats: total, by type, top beacons, RSSI distribution.
+    """
+    from sqlalchemy import case
+
+    filters = []
+    if start_time:
+        filters.append(BluetoothRecord.recorded_at >= start_time)
+    if end_time:
+        filters.append(BluetoothRecord.recorded_at <= end_time)
+
+    def _where(q):
+        return q.where(*filters) if filters else q
+
+    total = (await db.execute(_where(select(func.count(BluetoothRecord.id))))).scalar() or 0
+
+    # By record_type
+    type_result = await db.execute(_where(
+        select(BluetoothRecord.record_type, func.count(BluetoothRecord.id))
+        .group_by(BluetoothRecord.record_type)
+    ))
+    by_type = {row[0]: row[1] for row in type_result.all()}
+
+    # Top 20 beacons by record count
+    beacon_result = await db.execute(_where(
+        select(BluetoothRecord.beacon_mac, func.count(BluetoothRecord.id).label("cnt"))
+        .where(BluetoothRecord.beacon_mac.is_not(None))
+        .group_by(BluetoothRecord.beacon_mac)
+        .order_by(func.count(BluetoothRecord.id).desc())
+        .limit(20)
+    ))
+    top_beacons = [{"beacon_mac": row[0], "count": row[1]} for row in beacon_result.all()]
+
+    # RSSI distribution
+    rssi_result = await db.execute(_where(
+        select(
+            func.sum(case(((BluetoothRecord.rssi.is_not(None)) & (BluetoothRecord.rssi >= -50), 1), else_=0)).label("strong"),
+            func.sum(case(((BluetoothRecord.rssi < -50) & (BluetoothRecord.rssi >= -70), 1), else_=0)).label("medium"),
+            func.sum(case(((BluetoothRecord.rssi < -70) & (BluetoothRecord.rssi.is_not(None)), 1), else_=0)).label("weak"),
+            func.sum(case((BluetoothRecord.rssi.is_(None), 1), else_=0)).label("unknown"),
+        )
+    ))
+    rrow = rssi_result.one()
+    rssi_distribution = {
+        "strong_above_-50": int(rrow.strong or 0),
+        "medium_-50_-70": int(rrow.medium or 0),
+        "weak_below_-70": int(rrow.weak or 0),
+        "unknown": int(rrow.unknown or 0),
+    }
+
+    return APIResponse(data={
+        "total": total,
+        "by_type": by_type,
+        "top_beacons": top_beacons,
+        "rssi_distribution": rssi_distribution,
+    })
+
+
 @router.get(
     "/device/{device_id}",
     response_model=APIResponse[PaginatedList[BluetoothRecordResponse]],