- new BirthdaySyncDevice table + /api/birthdays/sync-report & /devices so the
web can show "birthdays come from these devices" (iOS reports its device on
each Contacts sync)
- settings: reject setting a birthday calendar as the group-visible calendar
(it can still be shared directly)
- web: Settings > Calendars > Birthdays shows the device list; exclude birthday
calendars from the group-visible picker
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
