```feat(user): 添加用户余额字段访问器

新增`getUserBalance`和`setUserBalance`方法，用于访问和修改用户余额字段。
```

src/main/java/com/muyu/common/system/domain/SysUser.java

@@ -177,4 +177,12 @@ public class SysUser extends BaseEntity {
     public String getPhonenumber () {
         return phonenumber;
     }
+
+    public Double getUserBalance() {
+        return userBalance;
+    }
+
+    public void setUserBalance(Double userBalance) {
+        this.userBalance = userBalance;
+    }
 }