feat: implement dark/light theme switching

- Add ui-settings resolution for v3.16.9
- Add CSS variables for dark/light themes in GlobalStyle
- Set default data-theme attribute on html element
- Simplify theme creation in Root.tsx
- Disable webpack error overlay for cleaner dev experience

packages/apps/webpack.serve.cjs

@@ -11,6 +11,9 @@ module.exports = merge(
   baseConfig(__dirname, 'development'),
   {
     devServer: {
+      client: {
+        overlay: false  // Disable error overlay
+      },
       headers: {
         'Content-Security-Policy': "frame-ancestors 'none'",
         'X-Frame-Options': 'DENY'