READ-ONLY shadow schema over the core-owned phoenix_kit_staff_people
table (created by core migration V100 — present on every install,
whether or not the phoenix_kit_staff package is). Part of the
staff-optional seam (see PhoenixKitProjects.People): projects' own
bounded read model of a person, mapping ONLY the columns this module
reads. No changesets — people are managed by the staff module's admin;
projects never writes these rows.
Struct identity: this is %PhoenixKitProjects.People.Person{}, never
interchangeable with %PhoenixKitStaff.Schemas.Person{} — do not pass
it into staff functions.