- Add first_day_of_week column to settings (0=Sunday, 1=Monday)
- Add Calendar section in Settings with toggle button
- Pass firstDay to FullCalendar from settings
- Align calendar toolbar and sidebar header to h-16 (matches UMBRA header)
- Remove border/padding wrapper from calendar grid for full-width layout
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
