261dae5990
All-day events showed on the correct day plus the next day because ICS DTEND for VALUE=DATE is exclusive (RFC 5545) but was treated as inclusive. Multi-day events using DURATION instead of DTEND were missing entirely. Birthday calendars were explicitly filtered out during Apple Calendar sync. Closes #5 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>