debug: 添加消息数组追踪日志

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

components/messages.tsx

@@ -283,6 +283,20 @@ function PureMessages({
     prevMessagesLengthRef.current = messages.length;
   }, [messages, scrollToBottom]);
 
+  // 🔍 调试：追踪消息数组变化
+  useEffect(() => {
+    console.log("[Messages] 📋 消息数组更新:", {
+      count: messages.length,
+      messages: messages.map(m => ({
+        id: m.id?.substring(0, 8),
+        role: m.role,
+        partsCount: m.parts?.length,
+        firstPartType: m.parts?.[0]?.type,
+        firstPartText: m.parts?.[0]?.type === "text" ? m.parts[0].text?.substring(0, 50) : undefined
+      }))
+    });
+  }, [messages]);
+  
   return (
     <div className="relative flex-1">
       <div