fix(chat): 阻止同会话并发 Agent Run 导致消息错乱

前端 submit 改用 chatStateRef 同步拦截连发；后端 createRun 检测同 session 活跃任务并返回 409，避免多条回复交错落库。

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

src/hooks/useTKMindChat.ts

@@ -1280,11 +1280,13 @@ export function useTKMindChat(
         (value) => typeof value === 'string' && value.trim(),
       );
       if (!text.trim() && normalizedImageUrls.length === 0) return;
+      // Use the ref here (not the React state) so that rapid back-to-back calls in the
+      // same render cycle are blocked even before the state update has been re-rendered.
       if (
-        chatState === 'streaming' ||
-        chatState === 'loading' ||
-        chatState === 'connecting' ||
-        chatState === 'waiting'
+        chatStateRef.current === 'streaming' ||
+        chatStateRef.current === 'loading' ||
+        chatStateRef.current === 'connecting' ||
+        chatStateRef.current === 'waiting'
       ) return;
 
       const trimmed = text.trim();
@@ -1319,6 +1321,9 @@ export function useTKMindChat(
       messageHistoryLoadedCountRef.current = messagesRef.current.length;
       setMessages(messagesRef.current);
       setChatState('waiting');
+      // Immediately reflect in the ref so any synchronous re-entry is blocked before
+      // the next React render cycle runs the useEffect that normally syncs this ref.
+      chatStateRef.current = 'waiting';
       setError(null);
       setPendingTool(null);
 
@@ -1484,7 +1489,6 @@ export function useTKMindChat(
     [
       notifyInsufficientBalance,
       session,
-      chatState,
       grantedSkills,
       clearActiveRequestMissingTimer,
       subscribeToSession,