refactor(chat): 优化候选查询排序逻辑

- 移除不必要的 limit(1) 操作以保留所有排序后的候选查询
- 保持按分数降序排列的排序规则不变

headless/chat/src/main/java/com/tencent/supersonic/headless/chat/ChatQueryContext.java

@@ -56,8 +56,7 @@ public class ChatQueryContext implements Serializable {
         candidateQueries = candidateQueries.stream()
                 .sorted(Comparator.comparing(
                         semanticQuery -> semanticQuery.getParseInfo().getScore(),
-                        Comparator.reverseOrder()))
-                .limit(1).collect(Collectors.toList());
+                        Comparator.reverseOrder())).collect(Collectors.toList());
         return candidateQueries;
     }