Deletes 21 Module.kt scaffolding objects that were never wired into any DI
registry. Removes unused imports across 8 production and 3 test files.
Restores StageExecutor, CyclePolicyResolver, PolicyValidation, and
ReplayContractTest — these are deferred features, not dead code.
Removes 6 files audited as fully unused: StageExecutor interface (shadowed
by kernel), CyclePolicyResolver and PolicyValidation (deferred cycle policy),
ApprovalRoutes (never registered), TuiNavigation (superseded by reducer),
and ReplayContractTest abstract class (no concrete subclasses).
ArtifactRelationshipType and CyclePolicy were audited but retained —
both are actively referenced by production code.