fix(client): 优化用户添加功能

- 修复到期时间判断逻辑，提高代码可读性
- 完善错误信息提示，方便排查问题

api/client/add.js

@@ -16,7 +16,7 @@ module.exports = async (ctx) => {
   if (!inbound?.success) return (ctx.body = { code: "1", msg: "获取节点失败" });
   const uuid = randomUUID();
   email = email || uuid.split("-")[0];
-  if (expiryTime!=0) {
+  if (expiryTime != 0) {
     expiryTime = dayjs(expiryTime, "YYYY-MM-DD HH:mm:ss").valueOf();
   }
   totalGB = totalGB * 1024 * 1024 * 1024;
@@ -37,7 +37,7 @@ module.exports = async (ctx) => {
   } else {
     ctx.body = {
       code: 1,
-      message: "添加失败",
+      message: "添加失败:" + result?.msg || "未知原因",
       data: ctx.request.body,
     };
   }