0a4545f042
Introduce CalendarStore.shared so Today, Calendar, and Onboarding read the same auth status and event cache instead of each spinning up its own EKEventStore. Trust the system's authoritative authorization status over the granted bool, debounce repeat permission requests, route denied users to Settings, and prompt when enabling local calendars without access. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>