8 tests covering daily / weekly / every-weekday / monthly / yearly expansion,
repeat-until cutoff, time-of-day preservation on the mapped local day, and
non-recurring single-day placement. Uses Calendar.current so it holds in any
timezone. Closes the recurrence-coverage gap from the calendar fix.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
