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

application/admin/validate/KeFuLeaveMessage.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace app\admin\validate;
+
+use think\Validate;
+
+class KeFuLeaveMessage extends Validate
+{
+    /**
+     * 验证规则
+     */
+    protected $rule = [];
+    /**
+     * 提示消息
+     */
+    protected $message = [];
+    /**
+     * 验证场景
+     */
+    protected $scene = [
+        'add'  => [],
+        'edit' => [],
+    ];
+
+}