style: update various code copy button and toc styles

- Removed the old copy-action SVG icon and replaced it with a new copy-button SVG icon.
- Added a new copy-success SVG icon for visual feedback on copy actions.
- Updated Waline component comments for clarity and improved code readability.
- Enhanced BackButton component with fallback navigation to homepage.
- Improved CodeCopyButton component by refining icon handling and timeout management.
- Adjusted GithubCard component's intersection observer root margin for better visibility.
- Updated GsapAnimation component variable names for consistency and clarity.
- Removed unnecessary styles from PhotoSwipe component.
- Modified TOC component styles for better spacing and layout.
- Updated multiple theme guide markdown files to correct image hosting URL comments.
- Cleaned up extend.css by removing commented-out styles and organizing code.
- Added PhotoSwipe background color and KaTeX overflow fixes to global.css.
- Enhanced markdown.css with video styling for better responsiveness.
- Improved transition.css comments for better understanding of GSAP animation states.

src/content/posts/guides/Theme Guide-en.md

@@ -187,8 +187,8 @@ preload: {
   // link prefetch strategies
   linkPrefetch: 'viewport' // hover, tap, viewport, load
   // image hosting url
-  imageHostURL: 'https://image.radishzz.cc'
   // optimize remote images in Markdown files to avoid cumulative layout shift
+  imageHostURL: 'https://image.radishzz.cc'
   // custom google analytics js
   // for users who route analytics javascript to a customized domain
   customGoogleAnalyticsJS: ''
@@ -271,7 +271,7 @@ getImageOptions: (_path, page) => ({
 [RSS feed page](https://retypeset.radishzz.cc/en/rss.xml) styles.
 
 ```html
-<!-- public/rss/rss-style.xsl -->
+<!-- public/feeds/xxx-style.xsl -->
 
 <style type="text/css">
 body{color:oklch(25% 0.005 298)} /* Font color */