P2-1: Guard SessionId NPE with safe-call in SessionsReducer
P2-2: Remove 16 dead event classes + reducer branches; replace with live orchestration events in tests
P2-3: Standardize ChatInput divergences — guard CancelSession, single-arg ProtocolError
P2-4: Remove dead TuiToolRecord.diff and ToolDisplayStatus.REQUESTED
P2-5: Remove dead streamLive from SessionEventBridge
P2-6: Extract SessionsReducerContext data class for 6+ param method
P2-7: Replace StageId("none") sentinel with TypeId.NONE
P2-9: Add TypeId.random() factory on all type-alias IDs
P2-10: Add KDoc on schemaVersion documenting reserved-for-migration
P2-8: Verified RouterReducer string-template already correct (TypeId value class toString)
Event log integrity (sole source of truth):
- SqliteEventStore: serialize append/appendAll under a Mutex, enable WAL +
busy_timeout + synchronous=NORMAL, roll back on any Throwable. Replaces the
app-computed `SELECT MAX(seq)+1` read-modify-write that dropped events under
concurrent appends (race was invisible to CI: only the in-memory store and
single-threaded :memory: tests were ever exercised).
- Serialization: encodeDefaults + ignoreUnknownKeys, explicit @SerialName on all
46 EventPayload subclasses and event-referenced enum constants, @Serializable on
RiskLevel/RiskAction. Guards the append-only log against silent corruption from
future class renames, field removals, or default-value changes.
Approval/grant security (Invariant: approvals cannot widen authority):
- Tier authorization is now a ceiling (request.tier.level <= max granted) instead
of set membership; SESSION grants bind to a specific toolName instead of matching
everything; handleCreateGrant rejects empty/over-tier/scopeless grants.
Router chat wiring (Phase 0-2): ChatInput round-trip, StartChatSession from IDLE,
router-panel layout, workflows behind Ctrl+W.
Tests: SqliteEventStore concurrency, serialization round-trip + discriminator
stability + unknown-key tolerance, adversarial grant scope/tier; updated existing
approval and reducer tests for the new grant semantics and StartChatSession effect.
fixed detekt issues where possible.
fixed disttar failing build because tools is added twice in the server module.
added workflowId where required.
fixed some tests not being recognized because of runBlocking without explicit return type.
formatting + imports.
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.
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.