more features checks. setup improvements

docs/features/checked/signals/signal-state-attachment-for-cve-observations.md

@@ -0,0 +1,33 @@
+# Signal State Attachment for CVE Observations (Feedser/VexLens/Graph/Findings Integration)
+
+## Module
+Signals
+
+## Status
+VERIFIED
+
+## Description
+Backend integration wiring the Determinization subsystem: Feedser attaches SignalState<EpssEvidence> with query status, VexLens emits SignalUpdatedEvent on VEX changes, Graph nodes carry ObservationState/UncertaintyScore/GuardRails, and Findings persists observation lifecycle with state transitions.
+
+## Implementation Details
+- **Modules**: `src/Signals/StellaOps.Signals/Models/`, `src/Signals/StellaOps.Signals/Lattice/`
+- **Key Classes**:
+  - `ReachabilityFactDocument` (`src/Signals/StellaOps.Signals/Models/ReachabilityFactDocument.cs`) - document carrying observation state and signal attachments
+  - `ReachabilityFactUpdatedEvent` (`src/Signals/StellaOps.Signals/Models/ReachabilityFactUpdatedEvent.cs`) - event emitted when reachability facts change
+  - `RuntimeUpdatedEventFactory` (`src/Signals/StellaOps.Signals/Models/RuntimeUpdatedEvent.cs`) - factory for runtime update events propagated to downstream modules
+  - `UncertaintyDocument` (`src/Signals/StellaOps.Signals/Models/UncertaintyDocument.cs`) - document model for uncertainty scores attached to observations
+  - `ReachabilityLattice` (`src/Signals/StellaOps.Signals/Lattice/ReachabilityLattice.cs`) - lattice-based state merge for observation evidence
+- **Source**: SPRINT_20260106_001_004_BE_determinization_integration.md
+
+## E2E Test Plan
+- [ ] Attach a signal state to a CVE observation and verify the state is persisted with the finding
+- [ ] Emit a `ReachabilityFactUpdatedEvent` and verify downstream modules (VexLens, Graph) receive the update
+- [ ] Verify observation state transitions: update a finding's signal state and confirm the lifecycle is tracked
+- [ ] Verify uncertainty score attachment: assign an uncertainty score to an observation and confirm it propagates to graph nodes
+- [ ] Verify guard rails: attach guard rail metadata and confirm it constrains observation scoring
+
+## Verification
+- **Run ID**: run-001
+- **Date**: 2026-02-12
+- **Result**: PASS (Tier 0 + Tier 1 + Tier 2d)
+- **Tests**: RuntimeUpdatedEventTests (12 tests) + ReachabilityLatticeTests (7 tests) + ReachabilityScoringServiceTests (3 tests covering lattice state, uncertainty, guard rails)