Event outcome constants

Named ESM constants for event-write outcomes, following the existing @blossm/duration-consts and @blossm/service-name-consts convention.

import { COMMITTED } from "@blossm/event-outcome-consts";

const thenFn = async ({ outcomes }) => {
  if (outcomes[0].status !== COMMITTED) return;
  return upgradeSession();
};

Exports: COMMITTED, DUPLICATE, QUEUED, UNKNOWN. These are stable wire values, shared by event stores, command handlers and application consumers. QUEUED is an event's unconfirmed write outcome; transport-level delivery uses @blossm/rpc-delivery-consts instead. Owning tests pin the serialized values.