chore: free-layout resbuild config (#87)

apps/demo-free-layout/rsbuild.config.ts

@@ -1,8 +1,9 @@
 import { pluginReact } from '@rsbuild/plugin-react';
+import { pluginLess } from '@rsbuild/plugin-less';
 import { defineConfig } from '@rsbuild/core';
 
 export default defineConfig({
-  plugins: [pluginReact()],
+  plugins: [pluginReact(), pluginLess()],
   source: {
     entry: {
       index: './src/app.tsx',