fix(lefu): 完善蓝牙连接状态处理，修复断开后 UI 不同步问题

- connectState 回调增加 UNAVAILABLE 清理和 READY 自动重连
- disconnect() 增加 _intentionalConnect 标记避免误重连
- deviceWillDisconnect 增加 _activeProtocol 防重入判断
- connectedDevice/equipment/connectedWifi 增加断开状态响应
- connectedWifi 设备断开后自动退出配网页

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

miniprogram/pages/equipment/equipment.ts

@@ -68,6 +68,7 @@ Page({
         lefuService.stopScan()
         lefuService.onDeviceConnect(() => {})
         lefuService.onDeviceInfo(() => {})
+        lefuService.onDisconnected(() => {})
     },
 
     /** 拉取已绑定设备列表，加载完成后检查缓存自动连接 */
@@ -112,6 +113,9 @@ Page({
         lefuService.onDeviceInfo((info) => {
             this._markConnected(info.serialNumber as string)
         })
+        lefuService.onDisconnected(() => {
+            this._markAllDisconnected()
+        })
         lefuService.autoConnect()
     },
 
@@ -124,6 +128,12 @@ Page({
         this.setData({ deviceList: list })
     },
 
+    /** 将所有设备标记为未连接 */
+    _markAllDisconnected() {
+        const list = this.data.deviceList.map(item => ({ ...item, connected: false }))
+        this.setData({ deviceList: list })
+    },
+
     /** 点击「连接」：扫描周边设备，找到 deviceId 匹配的设备后连接 */
     onTapConnect(e: WechatMiniprogram.TouchEvent) {
         const userInfo = e.currentTarget.dataset.userInfo as DeviceItem