feat(scale): 新增主从设备秤数据联网同步功能

- 新增 ScaleWebSocketServer/Client、ScaleDataAggregator、ScaleServiceManager 等秤服务模块
- 新增 MasterScaleActivity（主设备秤数据总览，按设备分组展示IP+秤列表）
- 新增 SlaveActivity（子设备专属页面，显示IP、主设备连接状态及本机秤数据）
- SlaveActivity 改为横屏，MasterScaleActivity 保持竖屏
- 子设备连接状态通过 WebSocket onOpen/onClose 回调实时更新
- GlobalData 新增 DeviceRole 枚举，BaseApp 启动时初始化角色并启动秤服务
- SettingActivity 新增设备角色展示和秤数据监控入口
- Weigher2 支持外部设置串口路径，适配不同硬件子设备

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

gradle/libs.versions.toml

@@ -30,6 +30,7 @@ refreshLayoutKernel = "3.0.0-alpha"
 refreshHeaderClassics = "3.0.0-alpha"
 refreshHeaderRadar = "3.0.0-alpha"
 roomRuntime = "2.5.2"
+java-websocket = "1.5.7"
 
 [libraries]
 android-core = { module = "com.google.zxing:android-core", version.ref = "androidCore" }
@@ -75,6 +76,7 @@ refresh-header-radar = { module = "io.github.scwang90:refresh-header-radar", ver
 refresh-header-classics = { module = "io.github.scwang90:refresh-header-classics", version.ref = "refreshHeaderClassics" }
 refresh-layout-kernel = { module = "io.github.scwang90:refresh-layout-kernel", version.ref = "refreshLayoutKernel" }
 retrofit = { module = "com.squareup.retrofit2:retrofit", version.ref = "converterGson" }
+java-websocket = { module = "org.java-websocket:Java-WebSocket", version.ref = "java-websocket" }
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }