fix(lefu): 搜索时 UNAVAILABLE 抖动不再清空协议，修复返回后设备误判断开

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

miniprogram/lefu/service.ts

@@ -187,10 +187,17 @@ class LeFuService {
 				this._doReconnect()
 				return
 			}
-			// 蓝牙不可用：做完整清理
+			// 蓝牙不可用：蓝牙真关了才清空协议；扫描/连接期间的 UNAVAILABLE 抖动（蓝牙还开着）保留协议
 			if (res === plugin.BLUE_STATE.UNAVAILABLE) {
+				let bluetoothOff = false
+				try { bluetoothOff = wx.getSystemSetting().bluetoothEnabled === false } catch (e) { bluetoothOff = false }
+				console.log(TAG, 'UNAVAILABLE 排查', { intentionalConnect: this._intentionalConnect, hasProtocol: !!this._activeProtocol, bluetoothOff })
 				this._stopKeepAlive()
 				this._stopReconnectTimer()
+				// 蓝牙还开着：只是抖动，保留协议，避免 isConnected 误判为 false
+				if (!bluetoothOff) {
+					return
+				}
 				if (this._activeProtocol) {
 					this._activeProtocol = null
 					this._onDisconnectedCbs.forEach(cb => cb())
@@ -220,7 +227,9 @@ class LeFuService {
 
 		// 即将断开：清理协议实例，若非主动断开则触发重连
 		plugin.bus.subscribe('deviceWillDisconnect', () => {
-			console.warn(TAG, 'bus[deviceWillDisconnect]，intentionalConnect:', this._intentionalConnect)
+			let bluetoothEnabled = ''
+			try { bluetoothEnabled = String(wx.getSystemSetting().bluetoothEnabled) } catch (e) { bluetoothEnabled = 'unknown' }
+			console.warn(TAG, 'deviceWillDisconnect 排查', { intentionalConnect: this._intentionalConnect, hasProtocol: !!this._activeProtocol, bluetoothEnabled })
 			this._stopKeepAlive()
 			if (this._activeProtocol) {
 				this._activeProtocol = null