- CalendarOccurrence: required reminderLeadMinutes: number | null (atomic mirror of expand.ts, Plan 11-03) - CreateEventPayload: optional reminderLeadMinutes?: number | null with absent/null/0/positive contract (D-08) - Update CalendarOccurrence fixtures in EventForm.test.tsx + EventDetailPopover.test.tsx to include the new required field (reminderLeadMinutes: null) - pwa tsc --noEmit exits 0