fix(scale): 子设备断线时从聚合器移除数据，修复列表不消失的问题

- ScaleWebSocketClient 新增 onDeviceDisconnected 回调，在 onFailure/onClosed 时触发
- ScaleServiceManager 绑定回调，断线时调用 aggregator.removeDevice() 清除缓存
- 重连成功后数据重新推送，UI 列表自动恢复

app/src/main/java/com/shuwei/dish/match/scale/ScaleServiceManager.kt

@@ -100,6 +100,7 @@ object ScaleServiceManager {
         // WebSocket 客户端
         val client = ScaleWebSocketClient().also {
             it.onScaleData = { data -> aggregator?.onRemoteScaleData(data) }
+            it.onDeviceDisconnected = { remoteId -> aggregator?.removeDevice(remoteId) }
         }
         wsClient = client
 

app/src/main/java/com/shuwei/dish/match/scale/ScaleWebSocketClient.kt

@@ -49,6 +49,9 @@ class ScaleWebSocketClient {
     /** 收到秤数据时的回调，在子线程调用 */
     var onScaleData: ((data: ScaleData) -> Unit)? = null
 
+    /** 设备断线时的回调（连接失败或关闭），在子线程调用 */
+    var onDeviceDisconnected: ((deviceId: String) -> Unit)? = null
+
     /**
      * 连接到指定子设备
      * @param deviceId 子设备 ID
@@ -85,12 +88,14 @@ class ScaleWebSocketClient {
             override fun onFailure(webSocket: WebSocket, t: Throwable, response: Response?) {
                 Log.w(TAG, "连接子设备失败: $deviceId, ${t.message}")
                 connections.remove(deviceId)
+                onDeviceDisconnected?.invoke(deviceId)
                 scheduleReconnect(deviceId, host, port)
             }
 
             override fun onClosed(webSocket: WebSocket, code: Int, reason: String) {
                 Log.d(TAG, "子设备连接已关闭: $deviceId, reason=$reason")
                 connections.remove(deviceId)
+                onDeviceDisconnected?.invoke(deviceId)
                 scheduleReconnect(deviceId, host, port)
             }
         })