fix(bus): use GlobalBus for InstanceDisposed in legacy subscribeAll

The sync callback API can't wait for async layer acquisition, so
delivering InstanceDisposed through the PubSub stream is a race
condition. Instead, the legacy subscribeAll adapter listens on
GlobalBus for InstanceDisposed matching the current directory.

The Effect service's stream ending IS the disposal signal for
Effect consumers — this is only needed for the legacy callback API.

Also reverts forceInvalidate, fiber tracking, priority-based
disposal, and other workaround attempts. Clean simple solution.