Summary

Strengthen the governance request store contract so persistence providers can protect request updates with optimistic concurrency instead of blind upsert semantics.

Goal

Replace the current unrestricted Store(...) behavior with a contract that can reject stale writes and preserve governance lifecycle correctness.

Scope

What should be implemented?

• Rework IMutationRequestStore so update semantics are explicit rather than blind overwrite
• Decide between contracts such as Create, Update, TryUpdate, Save(expectedRevision), or TryTransition
• Add request revision or equivalent persistence guard to the stored request model
• Define store behavior when expected revision or expected status does not match
• Update in-memory storage to follow the same contract
• Add regression coverage for blind overwrite scenarios

Acceptance Criteria

• Governance request storage no longer relies on unguarded upsert semantics for lifecycle updates
• Providers can reject stale writes explicitly
• The in-memory implementation follows the same concurrency contract as future real providers
• Test coverage proves blind overwrite behavior is no longer accepted for guarded lifecycle updates
• The change remains scoped to ModularityKit.Mutator.Governance

Notes

Implemented through:

• IMutationRequestStore.Create(...)
• IMutationRequestStore.TryStore(..., expectedRevision)
• MutationRequest.Revision
• MutationRequestAlreadyExistsException
• MutationRequestConcurrencyException
• updated InMemoryMutationRequestStore
• regression coverage in MutationRequestStoreContractTests

The old blind overwrite characterization was replaced by guarded store tests that assert duplicate creates and stale writes are rejected.