Add pointer-based gesture handling to the calendar for lateral navigation
(drag/swipe left/right) and pinch-to-zoom between temporal layers. Also
fix dark mode across 30+ canvas shape components by replacing hardcoded
white backgrounds and input styles with --rs-* CSS custom property
references (with light-mode fallbacks).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>