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_contract.php

@@ -0,0 +1,27 @@
+<?php
+
+return [
+    'Id'          => 'id',
+    'User_id'     => '用户',
+    'Coin_id'     => '币种',
+    'Symbol'      => '币种标识',
+    'Type'        => '类型',
+    'Type more'   => '做多',
+    'Type free'   => '做空',
+    'Status'      => '状态',
+    'Status 0'    => '待持仓',
+    'Status 1'    => '持仓中',
+    'Status 2'    => '已平仓',
+    'Status 3'    => '已撤销',
+    'Price'       => '持仓价格',
+    'Pc_price'    => '平仓价格',
+    'Num'         => '数量',
+    'Multiple'    => '倍数',
+    'Promise_fee' => '保证金',
+    'Fee'         => '手续费',
+    'Zy_price'    => '止盈价格',
+    'Zs_price'    => '止损价格',
+    'Createtime'  => '创建时间',
+    'Updatetime'  => '更新时间',
+    'Pctime'      => '平仓时间'
+];