feat(ui): add article TOC and interactive VRAM calculator for Wan 2.2

src/pages/posts/[...slug].astro

@@ -1,6 +1,7 @@
 ---
 import BaseLayout from '../../layouts/BaseLayout.astro';
 import AuthorCard from '../../components/AuthorCard.astro';
+import TableOfContents from '../../components/TableOfContents.astro';
 import { getCollection, render } from 'astro:content';
 import { postLang } from '../../lib/lang';
 import { countWords, readingMinutes } from '../../lib/reading-time';
@@ -16,7 +17,7 @@ export async function getStaticPaths() {
 }
 
 const { post } = Astro.props;
-const { Content } = await render(post);
+const { Content, headings } = await render(post);
 
 const lang = postLang(post.slug);
 
@@ -119,6 +120,8 @@ const jsonLd = {
       </figure>
     )}
 
+    <TableOfContents headings={headings} lang={lang} />
+
     <Content />
 
     <AuthorCard />