Website overhaul: nav, accessibility, shared components, SEO, Reaper silence detection

Website:
- Add persistent top nav across all pages
- Add skip-to-content links, focus-visible styles, ARIA on audio player
- Fix text contrast for WCAG AA compliance
- Add 600px breakpoint, mobile typography scaling
- Extract shared footer.js, player.js, episode.js components
- Episode pagination (10 + Load More), featured clip dedup
- Worker meta injection for social crawler OG tags
- Unify Plausible analytics proxy across all pages
- Sanitize innerHTML for XSS safety
- Custom 404 page, enhanced llms.txt, fix sitemap
- Bump cache versions to v=4

Reaper:
- Add dual silence threshold: 2.5s for speaker transitions, 6s for same-speaker gaps

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

website/sitemap.xml

@@ -234,12 +234,6 @@
     <changefreq>never</changefreq>
     <priority>0.7</priority>
   </url>
-  <url>
-    <loc>https://lukeattheroost.com/episode.html?slug=episode-32-tacos-taxes-and-tense-conversations</loc>
-    <lastmod>2026-03-09</lastmod>
-    <changefreq>never</changefreq>
-    <priority>0.7</priority>
-  </url>
   <url>
     <loc>https://lukeattheroost.com/episode.html?slug=episode-33-late-night-confessions-and-cosmic-comedies</loc>
     <lastmod>2026-03-11</lastmod>