feat: extend references and enhance analytics tracking
Reference pages:
- Add Transitions & Animations section (transition-*, animation-*)
- Add CSS Variables section (--*, var(), :root)
- Add Interactive Elements section (<details>, <summary>, <dialog>, <progress>, <meter>, <datalist>)
Analytics tracking (Umami v2):
- Add lesson_nav tracking for next/prev navigation
- Add lesson_select tracking for sidebar lesson clicks
- Add reset_code tracking for code resets
- Add help_open tracking for help dialog
- Add sidebar_open tracking for menu opens
- Add share_open and share_copy tracking for sharing
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Michael Czechowski
357f6dc57c