perf: address PageSpeed Insights issues (CLS, contrast, touch targets, JS minification)

- Reserve sidebar min-height on desktop to prevent CLS from Alpine.js hydration
- Defer lite-yt-embed.css with media="print" onload pattern
- Add terser JS minification in eleventy.after build hook
- Increase touch target sizing for category pills, facepile avatars, nav items
- Fix text-surface-400 contrast ratio (3.05:1 → 6.23:1) across 20 instances

Confab-Link: http://localhost:8080/sessions/edb1b7b0-da66-4486-bd9c-d1cfa7553b88

podroll.njk

@@ -87,7 +87,7 @@ permalink: /podroll/
                     <span x-text="episode.podcast?.title || 'Unknown'"></span>
                   </a>
                   <time class="font-mono text-sm" :datetime="episode.published" x-text="formatDate(episode.published)"></time>
-                  <span x-show="episode.enclosure" class="text-surface-400">
+                  <span x-show="episode.enclosure" class="text-surface-600 dark:text-surface-400">
                     <svg class="w-3 h-3 inline" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                       <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15.536 8.464a5 5 0 010 7.072m2.828-9.9a9 9 0 010 12.728M5.586 15.536a5 5 0 001.414 1.414m2.828-9.9a9 9 0 012.828-2.828"/>
                     </svg>