feat(studio): 回退/重roll 与 R5 用户确认下一步

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/Studio/StudioRunChat.jsx

@@ -49,17 +49,15 @@ function StudioRunChat({
 
   const lastUserIdx = findLastUserMessageIndex(stepMessages);
   const historyMessages =
-    lastUserIdx > 0 ? stepMessages.slice(0, lastUserIdx) : [];
+    lastUserIdx > 0
+      ? stepMessages.slice(0, lastUserIdx).filter((msg) => msg.role === 'user')
+      : [];
   const lastUserMessage =
     lastUserIdx >= 0 ? stepMessages[lastUserIdx] : pendingUserText
       ? { role: 'user', content: pendingUserText }
       : null;
 
-  const summaryText =
-    evaluation ||
-    (lastUserIdx >= 0 && stepMessages[lastUserIdx + 1]?.role === 'assistant'
-      ? stepMessages[lastUserIdx + 1].content
-      : null);
+  const summaryText = evaluation || null;
 
   const hasFocusContent =
     thinking || summaryText || pendingUserText || sending || lastUserMessage;
@@ -124,11 +122,9 @@ function StudioRunChat({
             {historyMessages.map((msg) => (
               <div
                 key={msg.id}
-                className={`studio-run-chat-history-item role-${msg.role}`}
+                className="studio-run-chat-history-item role-user"
               >
-                <span className="studio-run-chat-history-role">
-                  {msg.role === 'user' ? '你' : '助手'}
-                </span>
+                <span className="studio-run-chat-history-role">你</span>
                 <span className="studio-run-chat-history-text">{msg.content}</span>
               </div>
             ))}