-- ============================================================
-- HeavyHaul Agent — phone extension on trip participants (2026-09-04
-- workspace feedback). Nash: extension is NOT required, the phone IS
-- required; "four dispatchers from the same company use the same email
-- sometimes... maybe they use the same email, same phone number, but they
-- have different extensions. This is how we can find and pinpoint the
-- right user." The email+phone+extension cross-reference matching runs in
-- the backend phase; the field is stored now.
-- ============================================================

alter table public.trip_participants
  add column phone_ext text;