Synthetic campaign launch preparation

This boundary validates only the supplied envelope's shape and fail-closed facts. Trusted regional transaction code must still authenticate the actor, establish authorization identity, scope, and freshness, calculate and independently verify inputs, persist the immutable snapshot and audit event, mutate lifecycle state, create queue/outbox records, recheck time-sensitive controls, and dispatch through an approved regional provider.

No campaign, customer, contact, template, schedule, queue/outbox item, message, database row, audit event, production evidence, or provider request is created.