feat: 优化对话历史功能

frontend/src/components/ChatPanel/index.tsx

@@ -154,13 +154,13 @@ export function ChatPanel({
           </div>
         )}
 
-        {messages.map((msg, index) => (
+        {messages.map((msg) => (
           msg.role === "system" ? (
-            <div key={index} className="chat-message chat-message--system">
+            <div key={msg.id} className="chat-message chat-message--system">
               <span className="chat-message--system__text">{msg.content}</span>
             </div>
           ) : (
-            <div key={index} className={`chat-message chat-message--${msg.role}`}>
+            <div key={msg.id} className={`chat-message chat-message--${msg.role}`}>
               <div className="chat-message__role">
                 {msg.role === "user" ? t("chat.userLabel") : "AI"}
               </div>