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

uno.config.ts

@@ -2,7 +2,6 @@ import type { Theme } from 'unocss/preset-uno'
 import {
   defineConfig,
   presetAttributify,
-  presetTypography,
   presetUno,
   transformerDirectives,
   transformerVariantGroup,
@@ -16,7 +15,6 @@ export default defineConfig({
   presets: [
     presetUno(),
     presetAttributify(),
-    presetTypography(),
     presetTheme<Theme>({
       theme: {
         dark: {