feat: show investigation history

components/reasoning-workspace.jsx

@@ -212,8 +212,8 @@ function InvestigationHistoryCard({ turn }) {
       <div className="mt-2 space-y-2 text-sm">
         <p><strong>{turn.question}</strong></p>
         <p className="text-gray-700">{turn.answer}</p>
-        {turn.engineResponse && (
-          <p className="italic text-gray-500">{turn.engineResponse}</p>
+        {turn.acknowledgement && (
+          <p className="italic text-gray-500">{turn.acknowledgement}</p>
         )}
       </div>
     </details>
@@ -405,12 +405,12 @@ export default function ReasoningWorkspace({
         {
           question: typeof q === "string" ? q : q?.question ?? "",
           answer: lastSubmittedAnswer,
-          engineResponse: result?.summary || null,
+          acknowledgement: result?.summary || null,
           timestamp: Date.now(),
         },
       ]);
     }
-  }, [updateStatus, lastSubmittedAnswer]);
+  }, [updateStatus, lastSubmittedAnswer, result]);
 
   const { elapsed: startElapsed, currentMessage: startMsg } = useLoadingStatus(
     INITIAL_MESSAGES,
@@ -485,6 +485,9 @@ export default function ReasoningWorkspace({
           {graph && <SituationCard centralStatement={graph.centralStatement} />}
           {graph && <CurrentUnderstanding currentSummary={graph.currentSummary} />}
 
+          {/* ── Investigation history (below situation, above current focus) ─ */}
+          <InvestigationHistory turns={investigationHistory} />
+
           {/* Active investigation (only when we have a question to answer) */}
           {canAnswer && <CurrentInvestigationCard selectedQuestion={selectedQ} graph={graph} />}
           {canAnswer && <CurrentFocusCard graph={graph} />}
@@ -521,9 +524,6 @@ export default function ReasoningWorkspace({
             </form>
           )}
 
-          {/* ── Investigation history (below the answer form) ─ */}
-          <InvestigationHistory turns={investigationHistory} />
-
           {/* ── Developer details (collapsed by default) ─── */}
           {(status === "success" || status === "error") && graph && (
             <DeveloperDetails