Centralize all hardcoded rgba color values into CSS custom properties
and extract glass/glow styles into reusable utility classes (.glass,
.glass-inner, .glow-border, .glow-border--animated) in main.css.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Group events into five temporal sections with section headers, date subheaders,
and context-aware time display (clock time for upcoming, relative for past).
Includes new useEventGrouping composable, SectionHeader and DateSubheader
components, full unit and E2E test coverage.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
