For engineer + l1_tech roles, check_seat_available is called at each
mutation point. Returns 402 Payment Required with structured detail
{code: 'seat_limit_exceeded', role, current, limit, upgrade_url} when
seats are full. Grandfathering: existing over-seated accounts keep
existing users; only new mutations are blocked.
Also updates AccountInviteCreate and AccountRoleUpdate schemas to
accept l1_tech as a valid role value.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Michael Chihlas
47ff8ad2b5