LightningCSS (Vite 8) was stripping the unprefixed backdrop-filter when
it saw the manual -webkit- prefix, breaking blur effects in Firefox and
on production. Let LightningCSS handle prefixing automatically.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Introduces BottomSheet and RsvpBar components, integrates the RSVP
submission flow into EventDetailView, extends useEventStorage with
saveRsvp/getRsvp, and adds unit tests plus an E2E spec for the RSVP
workflow.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>