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/general/attachment.php

@@ -0,0 +1,31 @@
+<?php
+
+return [
+    'Id'                       => 'ID',
+    'Admin_id'                 => '管理员ID',
+    'User_id'                  => '会员ID',
+    'Url'                      => '物理路径',
+    'Imagewidth'               => '宽度',
+    'Imageheight'              => '高度',
+    'Imagetype'                => '图片类型',
+    'Imageframes'              => '图片帧数',
+    'Preview'                  => '预览',
+    'Filename'                 => '文件名',
+    'Filesize'                 => '文件大小',
+    'Mimetype'                 => 'Mime类型',
+    'Image'                    => '图片',
+    'Audio'                    => '音频',
+    'Video'                    => '视频',
+    'Text'                     => '文档',
+    'Application'              => '应用',
+    'Zip'                      => '压缩包',
+    'Extparam'                 => '透传数据',
+    'Createtime'               => '创建日期',
+    'Uploadtime'               => '上传时间',
+    'Storage'                  => '存储引擎',
+    'Upload to third'          => '上传到第三方',
+    'Upload to local'          => '上传到本地',
+    'Upload to third by chunk' => '上传到第三方(分片模式)',
+    'Upload to local by chunk' => '上传到本地(分片模式)',
+    'Upload from editor'       => '从编辑器上传'
+];