Add webinar registrants to their chosen event session

Your webinar signups sometimes land in the wrong session, leaving hosts without attendee context. Fix registrations so coordinators have correct session lists same day.

Overview

When registrants pick sessions but routing fails, hosts lose attendee context and pre-event outreach becomes inaccurate. This flow applies each choice to the correct session and updates registration lists automatically so coordinators can send correct pre-event communications the same day.