fix: 修复聊天排队和每日额度重置

ai_knowledge_base_v2/apps/backend/app/api/chat.py

@@ -113,7 +113,7 @@ async def _chat_stream(payload: ChatCompletionRequest, db: Session, current_user
         yield _sse_done()
         return
 
-    if queue_request.status == "queued" and queued_token is not None:
+    if queue_request.status == "queued" and queue_request.token is not None:
         yield _sse_event(
             "queued",
             message=f"当前请求较多，正在排队中，前方约 {max(queue_request.position - 1, 0)} 个请求。",