refactor: terminal result card states open closed

components/reasoning-workspace.jsx

@@ -223,6 +223,12 @@ function PlainLanguageCard({ summary }) {
 // ── Investigation history card (readable notebook style) ──────
 function InvestigationHistoryCard({ turn }) {
   const isCollapsed = turn._collapsed;
+  const isAnswered = Boolean(turn.answer?.trim());
+
+  const displayedQuestion =
+    isCollapsed && turn.question.length > 60
+      ? `${turn.question.slice(0, 60)}…`
+      : turn.question;
 
   return (
     <details
@@ -231,22 +237,25 @@ function InvestigationHistoryCard({ turn }) {
       open={!isCollapsed}
     >
       <summary className="cursor-pointer px-4 py-2 text-sm font-medium text-gray-700 hover:text-gray-900">
-        {isCollapsed ? "▶ " : "▼ "}
-        {"✓ "}
-        {turn.question.length > 60 && !isCollapsed
-          ? turn.question.slice(0, 60) + "…"
-          : turn.question}
+        {isAnswered && <span aria-hidden="true">✓ </span>}
+        {displayedQuestion}
       </summary>
 
-      <div className="px-4 pb-3 pt-1 space-y-2">
-        <p><strong>Your answer</strong></p>
+      <div className="space-y-2 px-4 pb-3 pt-1">
+        <p>
+          <strong>Your answer</strong>
+        </p>
         <p className="text-gray-700">{turn.answer}</p>
 
         {turn.acknowledgement && (
           <>
             <hr className="border-gray-200" />
-            <p><strong>What changed</strong></p>
-            <p className="italic text-gray-500">{turn.acknowledgement}</p>
+            <p>
+              <strong>What changed</strong>
+            </p>
+            <p className="italic text-gray-500">
+              {turn.acknowledgement}
+            </p>
           </>
         )}
       </div>