Update trial end date for onboarding physician deals

Unrecorded trial end dates on onboarding physician contracts delay follow-up and billing. Populate trial end dates from the start so coordinators and billing can act the same day.

Overview

When contracts enter onboarding without a recorded trial end date, follow-ups and billing get delayed and coordinators scramble. This flow computes and writes the trial-end date to the deal so coordinators and billing can act the same day and keep timelines intact.