docs: record closure reconciliation consolidation

docs/current-handoff.md

@@ -250,6 +250,14 @@ Experiment 54N tested whether an interpretation disagreement can be judged for m
 - Focused validation passed via `npx vitest run tests/reproduce-multi-turn-investigation.harness.test.js` (`67/67`).
 - The exact 60B.44 live closure case can now be rerun once with direct evidence for active-target clearing and final-question clearing.
 
+### 60B.55 closure-normalization consolidation
+
+- Consolidated the proven closure-normalization fix: reverse resolution reconciliation, same-turn stale `selectedQuestion` clearing before strict validation, prompt clarification that `selectedQuestion` must remain unresolved after applying the proposal, and repaired deterministic 60B.47 regression structure.
+- Focused verification passed via `npx vitest run tests/graph/apply-proposal.test.js tests/graph/prompt-builder.test.js -t "60B.49|60B.52|60B.54|60B.43|60B.11|replaces downstream pricing|selectedQuestion|resolution"` (`38 passed | 151 skipped`).
+- Verified exact negative closure state deterministically: customer resolved, decision resolved, both resolved IDs present, `activeUnknownNodeId = null`, `selectedQuestion = null`.
+- Existing forward reconciliation, fallback-to-real-unresolved target, 60B.43, 60B.11, pricing prerequisite-first, and prompt-builder selectedQuestion rule all remained green.
+- Repository is now ready for one bounded live rerun of the exact 60B.47 negative-outcome closure.
+
 ### When This Knowledge-Management Phase Is Complete
 
 Provisional criteria for review (all confirmed met by Experiment 38 cold-start test):

docs/experiment-60b55.md

@@ -0,0 +1,91 @@
+# Experiment 60B.55 — Closure-normalization consolidation
+
+**Date:** 2026-08-14
+**Branch:** `feature/closure-selection-reconciliation-v0.41`
+
+## Purpose
+
+Consolidate and commit the already-proven closure-normalization fix after focused regression verification.
+
+## Implementation state consolidated
+
+The committed fix consists of four bounded changes only:
+
+1. reverse resolution reconciliation
+   - `updatedNodes.newStatus = "resolved"`
+   - `-> resolvedUnknownNodeIds` automatically includes that existing unknown node
+
+2. stale same-turn selectedQuestion clearing
+   - if `selectedQuestion.nodeId` is resolved by the same proposal
+   - `-> selectedQuestion = null` before strict validation
+
+3. prompt clarification
+   - `selectedQuestion` must remain unresolved after applying the proposal
+   - if all consequential unknowns resolve, `selectedQuestion` must be null
+
+4. repaired deterministic 60B.47 negative-closure regression structure
+
+## Focused verification result
+
+Command run:
+
+```bash
+npx vitest run \
+  tests/graph/apply-proposal.test.js \
+  tests/graph/prompt-builder.test.js \
+  -t "60B.49|60B.52|60B.54|60B.43|60B.11|replaces downstream pricing|selectedQuestion|resolution"
+```
+
+Result:
+
+- PASS — `38 passed | 151 skipped`
+
+## Verified behaviours
+
+### Exact negative closure regression
+
+The exact 60B.47-shaped deterministic regression now passes through `applyValidatedProposal(...)` with:
+
+- customer factor resolved
+- decision resolved
+- `resolvedUnknownNodeIds` / resulting `resolvedNodeIds` containing both IDs
+- `activeUnknownNodeId = null`
+- `selectedQuestion = null`
+
+### Reconciliation invariants
+
+Verified preserved:
+
+- forward reconciliation
+- already-consistent proposal unchanged
+- no duplicate resolved IDs
+- non-unknown nodes are not auto-added
+- non-resolved statuses are not auto-added
+
+### Fallback preservation
+
+Verified preserved:
+
+- stale same-turn resolved selectedQuestion clears cleanly
+- another genuine unresolved candidate still becomes the fallback target
+
+### Existing behavioural regressions preserved
+
+Verified preserved:
+
+- 60B.43 terminal post-mutation closure regression
+- 60B.11 preferred-target behaviour
+- pricing prerequisite-first regression
+- prompt-builder selectedQuestion rule regression
+
+## What is now guaranteed
+
+The deterministic engine now normalizes same-turn closure structure coherently before strict validation:
+
+- resolved existing unknowns are represented in both status and `resolvedUnknownNodeIds`
+- a same-turn resolved `selectedQuestion` cannot survive as stale structure
+- strict validator semantics remain intact
+
+## What remains unproven
+
+The exact live negative-outcome closure still needs one bounded rerun after this deterministic fix to confirm the same end state through the live model-driven path.