v4.2.0

What's changed in v4.2.0

• feat: add cancellable OutboxDrainRunner (#203) (by @patrickleet)

  Immediate after-commit publish stays the fast path. This loop is the
  safety net: dispatch_batch until the outbox is empty, sleep when idle,
  back off on store errors, stop on abort.

  Worker id is drain: so claims never collide with
  microsvc-immediate:. Service::outbox_drain builds the runner;
  spawn_outbox_publish_loop now wraps it. Dropping the handle leaves the
  task running; stop() aborts.

  Implements [[tasks/outbox-background-drain-runner]]

See full diff: v4.1.1...v4.2.0