cf2ef77bb0
RSVPs now carry a status ('yes'/'no'). When auth is enabled, answering
requires login for all events, not just capped ones. Answers are deduped
one per user and re-answering updates in place. A 'no' zeroes plus_one,
is excluded from Going counts and cap math, frees the person's slot
claims, and shows in a separate "Can't make it" list.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>