experiment(confidence-engine): isolate reconstruction observation

scripts/start-case-experiment-helper.cjs

@@ -64,6 +64,7 @@ async function runStartCaseExperiment(scenarioInput, experimentInstruction, opti
   let startCase = options.startCase;
   let reconstructionProvider = options.reconstructionProvider;
   let reconstructionModelName = options.reconstructionModelName;
+  let reconstructionOnly = options.reconstructionOnly;
   const isMock = process.env.START_CASE_EXPERIMENT_HELPER_MOCK === "1";
 
   if (process.env.START_CASE_EXPERIMENT_PROVIDER === "openai") {
@@ -80,6 +81,7 @@ async function runStartCaseExperiment(scenarioInput, experimentInstruction, opti
       fetchImpl: fetch,
     });
     reconstructionModelName = "gpt-5.6-terra";
+    reconstructionOnly = true;
   }
 
   if (!startCase && isMock) {
@@ -120,6 +122,7 @@ async function runStartCaseExperiment(scenarioInput, experimentInstruction, opti
     result = await startCase(scenarioInput, {
       reconstructionProvider,
       reconstructionModelName,
+      reconstructionOnly,
     });
   } finally {
     // Clean up experiment env var after execution regardless of outcome
@@ -141,6 +144,7 @@ async function runStartCaseExperiment(scenarioInput, experimentInstruction, opti
   return {
     success: result.success,
     summary: result.summary ?? null,
+    reconstruction: result.reconstruction ?? null,
     situationGraphNodeCount: result.situationGraph?.nodes?.length ?? 0,
     situationGraphEdgeCount: result.situationGraph?.edges?.length ?? 0,
     selectedQuestion: result.selectedQuestion?.question ?? null,
@@ -148,6 +152,7 @@ async function runStartCaseExperiment(scenarioInput, experimentInstruction, opti
     assessmentProgress: result.assessment?.progress ?? null,
     endToEndElapsedMs: Date.now() - endToEndStartedAt,
     diagnostics: result.diagnostics ?? null,
+    providerApiPath: result.providerApiPath ?? null,
     error: result.success ? null : (result.error ?? "unknown"),
     statusCode: result.statusCode ?? (result.success ? 200 : 500),
   };