feat(mdx): add MDX support and migrate markdown files to MDX

- Add @astrojs/mdx integration to enable MDX support
- Migrate all markdown files (.md) to MDX (.mdx) format
- Create HighlightBox component for enhanced content styling
- Update astro config to include MDX integration
- Add documentation guide for MDX integration

package.json

@@ -16,6 +16,7 @@
     "astro": "astro"
   },
   "dependencies": {
+    "@astrojs/mdx": "^4.3.0",
     "@astrojs/react": "^4.2.1",
     "@astrojs/sitemap": "^3.4.1",
     "@radix-ui/react-scroll-area": "^1.2.9",