Add colorMode to respect user's light/dark theme preference

Introduced a colorMode section in the Docusaurus config to set the default mode to light, enable the color mode switch, and respect the user's preferred color scheme.

Author: josh-wong

docusaurus.config.js

@@ -571,6 +571,11 @@ const config = {
         textColor: '#FFFFFF',
         isCloseable: false,
       },
+      colorMode: {
+        defaultMode: 'light',
+        disableSwitch: false,
+        respectPrefersColorScheme: true,
+      },
       zoom: {
         selector: '.markdown :not(em) > img',
         background: {