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ApprovalRoutes (never registered), TuiNavigation (superseded by reducer),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.
New core:artifacts-store interface + infrastructure/artifacts-cas
implementation: segment files + SQLite index, Blake3 hashing,
group-commit fsync via flushBefore, recovery tail-scan, manual
compactor, and oldest-first disk-cap evictor.
Inference events now carry promptArtifactId / responseArtifactId;
orchestrators put bytes before emitting. SqliteEventStore wraps
its txn in artifactStore.flushBefore so segment data is fsynced
before the event commit, making the crash window non-corrupting
(TailScanner re-indexes orphan tail records on reopen).
Compactor and evictor are mutually exclusive via maintenanceMutex.
Step 9 (cloud sync) deferred to a later epic.
See docs/reviews/2026-05-18-cas-steps-1-8-review.md for the final
review.
kami