separate and improve conversation agent

frontend/lib/chat_screen.dart

@@ -95,7 +95,9 @@ class _ChatScreenState extends State<ChatScreen> {
       _title = chatInfo.name;
 
       currentThreadId = initialMessages.last.threadId;
-      if (currentThreadId != null) {
+      if (currentThreadId == null) {
+        createThread();
+      } else {
         expandedThreads.add(currentThreadId!);
       }
     });
@@ -151,9 +153,10 @@ class _ChatScreenState extends State<ChatScreen> {
     });
   }
 
-  void sendMessage(String content) {
+  void sendMessage(String content) async {
     if (content.trim().isEmpty) return; // Don't send empty messages
     _textController.clear();
+
     final newMessage = Message(sender: "user", content: content, threadId: currentThreadId);
     Backend.sendAction("send-chat-message", {
       'chatId': widget.chatId,