fix: make graph-backed questions authoritative

docs/v0.7-question-simplicity-experiment.md

@@ -23,6 +23,8 @@ That violated the intended one-step reasoning discipline.
 
 The engine should ask one question about one primary concept at a time.
 
+**The reconstruction model may suggest a question, but only the graph-backed deterministic pipeline may select the user-facing question.**
+
 ## One-question / one-concept rule
 
 Every user-facing question should:
@@ -85,6 +87,46 @@ This question:
 - stays graph-backed
 - avoids pricing or budget before problem existence is established
 
+## Start-case authority rule
+
+There were previously two question paths during initial analysis:
+
+- reconstruction model `nextQuestion`
+- graph-backed unknown selection and question formulation
+
+The defect was that `startCase` copied the reconstruction `nextQuestion` directly into the normal UI.
+
+That path is now closed.
+
+Initial user-facing questioning now follows this pipeline:
+
+```text
+reconstruction
+→ graph build
+→ unresolved unknown selection
+→ atomicity assessment
+→ decomposition if needed
+→ investigation strategy
+→ question formulation
+→ complexity validation
+→ selectedQuestion
+```
+
+The reconstruction question is still retained in diagnostics as provenance, but it is not authoritative.
+
+## Live result
+
+Running the commercial-method scenario through the real environment now:
+
+- succeeds without the enum compatibility failure
+- does not show the broad reconstruction question in the UI path
+- surfaces a graph-backed first question instead
+- keeps the reconstruction question only in diagnostics
+
+For the tested scenario, the user-facing first question remained:
+
+> Who experiences this problem?
+
 ## Remaining limitations
 
 - question-complexity assessment is still conservative and pattern-based rather than semantic in a richer linguistic sense