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/lang/zh-cn/app/app_currency.php

@@ -0,0 +1,31 @@
+<?php
+
+return [
+    'Id'            => 'id',
+    'Name'          => '币种名',
+    'Full_name'     => '全称',
+    'Exchange'      => '转换率(美元标准)',
+    'Suffix'        => '货币后缀',
+    'Thumb_image'   => '缩略图',
+    'Process'       => '提现手续费(个)',
+    'Is_reg'        => '是否可充值',
+    'Is_reg 1'      => '是',
+    'Is_reg 0'      => '否',
+    'Is_wid'        => '是否可提现',
+    'Is_wid 1'      => '是',
+    'Is_wid 0'      => '否',
+    'Min_widthdraw' => '提现最小金额',
+    'Max_widthdraw' => '提现最大金额',
+    'Is_tran'       => '是否可划转',
+    'Is_otc'        => '是否支持C2C交易',
+    'Is_otc 1'      => '是',
+    'Is_otc 0'      => '否',
+    'Min_hang'      => 'C2C最低挂单数量',
+    'Max_hang'      => 'C2C最高挂单数量',
+    'Status'        => '状态',
+    'Status 0'      => '显示',
+    'Status 1'      => '隐藏',
+    'Createtime'    => '创建时间',
+    'Updatetime'    => '更新时间',
+    'Weigh'         => '权重'
+];