- Plugin: use bus.subscribeAll() Stream + forkScoped instead of callback facade
- Vcs: use bus.subscribe() Stream + forkScoped instead of acquireRelease callback
- Status: use bus.publish() Effect directly instead of Effect.promise wrapper
- Rewrite Vcs test to use facade functions (shared memoMap ensures singleton Bus)
- Add Bus integration tests for subscribe cleanup and instance disposal
- Add runCallback to makeRuntime (returns interrupt function directly)
- Simplify forkStream to use runCallback instead of runFork + Fiber.interrupt
- Add 6 bus tests covering publish/subscribe, unsubscribe, subscribeAll,
and InstanceDisposed delivery on instance disposal