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.

package.json

@@ -20,7 +20,7 @@
     "@astrojs/rss": "^4.0.11",
     "@astrojs/sitemap": "^3.2.1",
     "@rehype-pretty/transformers": "^0.13.2",
-    "@unocss/reset": "^65.4.2",
+    "@unocss/reset": "^65.4.3",
     "astro": "^5.1.8",
     "astro-compress": "^2.3.6",
     "astro-robots-txt": "^1.0.0",
@@ -34,7 +34,7 @@
     "rehype-katex": "^7.0.1",
     "rehype-pretty-code": "^0.14.0",
     "rehype-slug": "^6.0.0",
-    "remark-directive": "^3.0.0",
+    "remark-directive": "^3.0.1",
     "remark-github-admonitions-to-directives": "^2.1.0",
     "remark-math": "^6.0.0",
     "remark-sectionize": "^2.1.0",
@@ -45,20 +45,19 @@
     "vite": "^6.0.11"
   },
   "devDependencies": {
-    "@antfu/eslint-config": "^3.15.0",
+    "@antfu/eslint-config": "^3.16.0",
     "@types/markdown-it": "^14.1.2",
-    "@types/mdast": "^4.0.4",
     "@types/node": "^22.10.7",
     "@types/sanitize-html": "^2.13.0",
-    "@unocss/eslint-plugin": "^65.4.2",
-    "@unocss/preset-attributify": "^65.4.2",
+    "@unocss/eslint-plugin": "^65.4.3",
+    "@unocss/preset-attributify": "^65.4.3",
     "astro-eslint-parser": "^1.1.0",
     "eslint": "^9.18.0",
     "eslint-plugin-astro": "^1.3.1",
     "lint-staged": "^15.4.1",
     "mdast-util-to-string": "^4.0.0",
     "reading-time": "^1.5.0",
-    "unocss": "^65.4.2",
+    "unocss": "^65.4.3",
     "unocss-preset-theme": "^0.14.1"
   },
   "lint-staged": {