feat: enhance typography and image handling

- Add Heti typography plugin for improved Chinese text layout
- Implement rehype plugin to convert images to figure elements with captions
- Update UnoCSS configuration by removing typography preset
- Modify file extensions for consistency (.mjs to .js)
- Add new plugins for admonition, GitHub card, and reading time components
- Improve image and text styling with Heti CSS

src/layouts/Layout.astro

@@ -13,6 +13,7 @@ import Head from '@/layouts/Head.astro'
 import { getPagePath } from '@/utils/path'
 import '@/styles/font.css'
 import '@/styles/global.css'
+import '@/styles/heti.css'
 import '@/styles/photoswipe.css'
 
 interface Props {