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/auth/admin.php

@@ -0,0 +1,9 @@
+<?php
+
+return [
+    'Group'                         => '所属组别',
+    'Loginfailure'                  => '登录失败次数',
+    'Login time'                    => '最后登录',
+    'Please input correct username' => '用户名只能由3-12位数字、字母、下划线组合',
+    'Please input correct password' => '密码长度必须在6-16位之间，不能包含空格',
+];

application/admin/lang/zh-cn/auth/group.php

@@ -0,0 +1,12 @@
+<?php
+
+return [
+    'The parent group can not be its own child'                            => '父组别不能是自身的子组别',
+    'The parent group can not found'                                       => '父组别未找到',
+    'Group not found'                                                      => '组别未找到',
+    'Can not change the parent to child'                                   => '父组别不能是它的子组别',
+    'Can not change the parent to self'                                    => '父组别不能是它的子组别',
+    'You can not delete group that contain child group and administrators' => '你不能删除含有子组和管理员的组',
+    'The parent group exceeds permission limit'                            => '父组别超出权限范围',
+    'The parent group can not be its own child or itself'                  => '父组别不能是它的子组别及本身',
+];

application/admin/lang/zh-cn/auth/rule.php

@@ -0,0 +1,20 @@
+<?php
+
+return [
+    'Toggle all'                                                => '显示全部',
+    'Condition'                                                 => '规则条件',
+    'Remark'                                                    => '备注',
+    'Icon'                                                      => '图标',
+    'Alert'                                                     => '警告',
+    'Name'                                                      => '规则',
+    'Controller/Action'                                         => '控制器名/方法名',
+    'Ismenu'                                                    => '菜单',
+    'Search icon'                                               => '搜索图标',
+    'Toggle menu visible'                                       => '点击切换菜单显示',
+    'Toggle sub menu'                                           => '点击切换子菜单',
+    'Menu tips'                                                 => '父级菜单无需匹配控制器和方法,子级菜单请使用控制器名',
+    'Node tips'                                                 => '控制器/方法名,如果有目录请使用 目录名/控制器名/方法名',
+    'The non-menu rule must have parent'                        => '非菜单规则节点必须有父级',
+    'Can not change the parent to child'                        => '父组别不能是它的子组别',
+    'Name only supports letters, numbers, underscore and slash' => 'URL规则只能是小写字母、数字、下划线和/组成',
+];