Refactor event processing to use Projector from eventstore library (#29)

* Replace EventuallyConsistentEventProcessor with Projector-based ProjectorProcessor

Delegate all projection mechanics (bookmarks, batching, BatchAwareProjection
callbacks) to the Projector from the eventstore library. The new
ProjectorProcessor is a thin lifecycle wrapper providing background thread
management, leader election modes, and start/stop/terminate control.

- Add ProjectorProcessor wrapping Projector with Processor interface
- Update ReadModelModule, OutboundModule, InboundModule to use ProjectorProcessor
- ReadModelAdapter: simplify to implement BatchAwareProjection only (inherits Projection)
- DispatcherAdapter, TranslatorAdapter: implement Projection (add eventQuery())
- Delete EventuallyConsistentEventProcessor (replaced by ProjectorProcessor)
- Retain ThrowableAndEventReference and ExceptionWhileHandlingEventWithReference

https://claude.ai/code/session_01QZvR1DxHBahjCzmcLQcoZG

* Use EventReference.happenedAfter() instead of raw position comparison

Position alone is not sufficient to determine event ordering.
Use the semantic happenedAfter() method consistent with the rest
of the codebase (e.g. DCBCommandContextImpl).

https://claude.ai/code/session_01QZvR1DxHBahjCzmcLQcoZG

* Remove orphaned exception classes no longer used after Projector migration

ThrowableAndEventReference and ExceptionWhileHandlingEventWithReference were
only used by EventuallyConsistentEventProcessor for manual exception unwrapping.
ProjectorProcessor delegates error handling to the eventstore Projector, which
surfaces errors via ProjectorException directly.

https://claude.ai/code/session_01QZvR1DxHBahjCzmcLQcoZG

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Co-authored-by: Claude <noreply@anthropic.com>

Author: vanrogu