The bus reads its user list from a file that, until the broker step adopts it as the nats module,
only the installer writes, and the installer wrote it only at enrolment. The build agent's account,
minted with step 13's push, never reached the bus; the agent was refused (Authorization Violation)
and the sdk step's build waited until it was killed. Every push genesis makes now places the composed
list and has the bus re-read it, until the nats module is registered (ADR 0331 §5, ADR 0333 §4).
jochen