fix: 解决不登陆无法问答问题；修复余额不足后流不关闭问题；

ruoyi-modules/ruoyi-chat/src/main/java/org/ruoyi/chat/service/chat/impl/ChatCostServiceImpl.java

@@ -435,8 +435,8 @@ public class ChatCostServiceImpl implements IChatCostService {
     @Override
     public boolean checkBalanceSufficient(ChatRequest chatRequest) {
         if (chatRequest.getUserId() == null) {
-            log.warn("checkBalanceSufficient->用户ID为空，视为余额不足");
-            return false;
+            log.warn("当前未登录");
+            return true;
         }
 
         try {

ruoyi-modules/ruoyi-chat/src/main/java/org/ruoyi/chat/service/chat/proxy/BillingChatServiceProxy.java

@@ -34,7 +34,16 @@ public class BillingChatServiceProxy implements IChatService {
             String errorMsg = "余额不足，无法使用AI服务，请充值后再试";
             log.warn("余额不足阻止AI回复，用户ID: {}, 模型: {}",
                      chatRequest.getUserId(), chatRequest.getModel());
-            throw new RuntimeException(errorMsg);
+            try {
+                emitter.send(errorMsg);
+                emitter.complete();
+            } catch (IOException e) {
+                log.error("推送流异常，用户ID: {}, 模型: {}",
+                        chatRequest.getUserId(), chatRequest.getModel());
+                emitter.complete();
+                throw new RuntimeException(errorMsg);
+            }
+            return emitter;
         }
 
         log.debug("余额检查通过，开始AI回复，用户ID: {}, 模型: {}",