docs: clarify Confidence Engine context authority

docs/investigation-state-assessment.md

@@ -1,8 +1,15 @@
 # Investigation State Assessment — Architectural Specification
 
-> **Status: Implemented (Experiment 18). First executable slice deployed.**
+> **Status: Passive / Experimental Implementation**
+> Implemented in code during Experiments 18–25B but does not control active user-facing investigation routing.
+> The capability records signals for future use; it is not current authority over the investigation path.
 > Design evolved through experiments; implementation validates and adjusts the spec iteratively.
 
+## Implementation status
+
+- **Implemented in code**: Yes — first executable slice deployed (Experiment 18).
+- **Active routing authority**: No — passive experimental capability isolated from user-facing investigation.
+
 ---
 
 ## Purpose
@@ -373,4 +380,4 @@ User
 
 Each arrow is a data flow. Each layer has a single responsibility. The assessment layer does not decide, reason, present, or converse — it describes the investigation's current state through multiple analytical dimensions so that behaviour selection can act on state rather than implementation details.
 
-This is an emerging architectural direction. It is intentionally recorded before implementation so future experiments remain aligned.
+This architectural description was captured during Experiment 18 and preserved as evidence of the assessment capability's design rationale. The capability is implemented in code but remains passive/experimental — it does not control the active user-facing investigation path. Future experiments may integrate these signals or replace them; this document records the design that was tested.