feat: enable live component rendering in MDX docs

- Register all 24 components in mdx-components.tsx via client boundary
- MDX files can now render real components inline (not just code blocks)
- media.mdx updated with live Figure and PullQuote demos

packages/docs/mdx-components.tsx

@@ -1,9 +1,19 @@
 import type { MDXComponents } from 'mdx/types';
 import defaultMdxComponents from 'fumadocs-ui/mdx';
+import {
+  Layout, Section, Article, Layer, Masthead, Rule, Footer,
+  Headline, Subhead, Kicker, BodyText, Quote, Byline, Dateline, Caption,
+  Image, Figure, Video, PullQuote,
+  BreakingNewsBanner, Folio, IndexBox, Factbox, RelatedArticles, AuthorCard,
+} from './lib/nui-client';
 
 export function useMDXComponents(components: MDXComponents): MDXComponents {
   return {
     ...defaultMdxComponents,
     ...components,
+    Layout, Section, Article, Layer, Masthead, Rule, Footer,
+    Headline, Subhead, Kicker, BodyText, Quote, Byline, Dateline, Caption,
+    Image, Figure, Video, PullQuote,
+    BreakingNewsBanner, Folio, IndexBox, Factbox, RelatedArticles, AuthorCard,
   };
 }