Relay MeshHub de integração orientado a eventos

export async function advance(orderId: string, event: DomainEvent) {
  await db.transaction(async (tx) => {
    const saga = await tx.sagas.lockById(orderId); // SELECT … FOR UPDATE
    const step = saga.transition(event); // pure: returns next state + commands
    await tx.sagas.save(saga.id, step.state);
    for (const command of step.commands) {
      await tx.outbox.insert({
        topic: command.topic,
        payload: command.payload,
        // Same source event => same key => the ERP applies it once.
        idempotencyKey: `${event.id}:${command.topic}`,
        traceId: event.traceId,
      });
    }
  });
}