W-03: invite_member now verifies the target user has a reciprocal
UserConnection row before sending the invite.
W-04: CalendarMember relationships changed from lazy="selectin" to
lazy="raise". All queries that access .user, .calendar, or .inviter
already use explicit selectinload() — verified across all routers
and services.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>