feat: 后端全量更新 - 含所有本次需求

- Contract.php: 返回合约账户余额(balance_contract)
- My.php: 地址管理增加BTC/ETH
- AppContract.php: 一键平仓(closeall)
- AppProxy.php: 代理专属注册链接 + 分级权限(L1/L2)
- site.php: 手续费减半(0.018→0.009)
- agent_permission_setup.sql: 代理权限SQL
- crypto_news_crawler.py: 新闻自动采集脚本

thinkphp/library/traits/think/Instance.php

@@ -0,0 +1,54 @@
+<?php
+// +----------------------------------------------------------------------
+// | ThinkPHP [ WE CAN DO IT JUST THINK ]
+// +----------------------------------------------------------------------
+// | Copyright (c) 2006~2018 http://thinkphp.cn All rights reserved.
+// +----------------------------------------------------------------------
+// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
+// +----------------------------------------------------------------------
+// | Author: liu21st <liu21st@gmail.com>
+// +----------------------------------------------------------------------
+
+namespace traits\think;
+
+use think\Exception;
+
+trait Instance
+{
+    /**
+     * @var null|static 实例对象
+     */
+    protected static $instance = null;
+
+    /**
+     * 获取示例
+     * @param array $options 实例配置
+     * @return static
+     */
+    public static function instance($options = [])
+    {
+        if (is_null(self::$instance)) self::$instance = new self($options);
+
+        return self::$instance;
+    }
+
+    /**
+     * 静态调用
+     * @param string $method 调用方法
+     * @param array  $params 调用参数
+     * @return mixed
+     * @throws Exception
+     */
+    public static function __callStatic($method, array $params)
+    {
+        if (is_null(self::$instance)) self::$instance = new self();
+
+        $call = substr($method, 1);
+
+        if (0 !== strpos($method, '_') || !is_callable([self::$instance, $call])) {
+            throw new Exception("method not exists:" . $method);
+        }
+
+        return call_user_func_array([self::$instance, $call], $params);
+    }
+}