feat:实现Windows系统通知功能

- 集成node-notifier实现跨平台系统通知
   - AI响应完成时自动弹出Windows Toast通知
   - 支持通知防抖机制，避免频繁弹窗
   - 添加通知配置项：启用/禁用、声音、超时时间
   - 移除VS Code内置弹窗，仅在系统通知失败时作为备用

webpack.config.js

@@ -20,7 +20,8 @@ const extensionConfig = {
     libraryTarget: 'commonjs2'
   },
   externals: {
-    vscode: 'commonjs vscode' // the vscode-module is created on-the-fly and must be excluded. Add other modules that cannot be webpack'ed, 📖 -> https://webpack.js.org/configuration/externals/
+    vscode: 'commonjs vscode', // the vscode-module is created on-the-fly and must be excluded. Add other modules that cannot be webpack'ed, 📖 -> https://webpack.js.org/configuration/externals/
+    'node-notifier': 'commonjs node-notifier' // node-notifier 依赖原生模块，必须排除
     // modules added here also need to be added in the .vscodeignore file
   },
   resolve: {