chore: remove unused dependencies, enhance scrollbar functionality, and update VSCode settings

- Removed unused `@types/mdast` dependency from package.json and pnpm-lock.yaml.
- Introduced a custom scrollbar component with theme support in Scrollbar.astro.
- Updated Layout.astro to include the new Scrollbar component.
- Enhanced ThemeToggle.astro to dispatch a theme-changed event on toggle.
- Added global scrollbar styles to global.css and created a new scrollbar.css for custom scrollbar styling.
- Updated VSCode settings to improve editor experience and added recommendations for new extensions.

uno.config.ts

@@ -25,10 +25,6 @@ export default defineConfig({
       },
     }),
   ],
-  transformers: [
-    transformerDirectives(),
-    transformerVariantGroup(),
-  ],
   theme: {
     colors: light,
     fontFamily: {
@@ -39,4 +35,10 @@ export default defineConfig({
       custom: ['EarlySummer-custom', 'ui-serif', 'Georgia', 'Cambria', 'Times New Roman', 'Times', 'serif'],
     },
   },
+  shortcuts: [],
+  rules: [],
+  transformers: [
+    transformerDirectives(),
+    transformerVariantGroup(),
+  ],
 })