feat(docusaurus.config): Add color mode configuration

This commit adds a new configuration for the color mode in the `docusaurus.config.ts` file. The `colorMode` object is added with properties to set the default mode to 'dark' and respect the user's preferred color scheme. This allows users to have a consistent color mode experience on the website.

docusaurus.config.ts

@@ -70,7 +70,7 @@ const config: Config = {
           to: 'https://apollo.volvox.tech',
         },
         {
-          to: '/apollo-docs',
+          to: '/apollo-docs/',
           position: 'left',
           label: 'Home'
         },
@@ -139,6 +139,10 @@ const config: Config = {
       darkTheme: prismThemes.oneDark,
       additionalLanguages: ['json']
     },
+    colorMode: {
+      defaultMode: 'dark',
+      respectPrefersColorScheme: true,
+    },
   } satisfies Preset.ThemeConfig,
 
   // Custom Plugins