chore(vscode-ide-companion): add testing infrastructure and improve config files

添加测试基础设施和改进配置文件：
- 添加 vitest.config.js 用于单元测试配置
- 配置测试覆盖率报告（v8 provider）
- 修复 postcss.config.js 的 eslint 警告
- 设置测试环境为 Node.js

packages/vscode-ide-companion/postcss.config.js

@@ -1,6 +1,7 @@
+/* eslint-disable no-undef */
 module.exports = {
   plugins: {
     tailwindcss: {},
     autoprefixer: {},
-  }
-}
+  },
+};

packages/vscode-ide-companion/vitest.config.js

@@ -0,0 +1,15 @@
+import { defineConfig } from 'vitest/config';
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    include: ['src/**/*.test.ts'],
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'json', 'html', 'clover'],
+      include: ['src/**/*.ts'],
+      exclude: ['src/**/*.test.ts', 'src/**/*.d.ts'],
+    },
+  },
+});
+//# sourceMappingURL=vitest.config.js.map