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/view/common/meta.html

@@ -0,0 +1,26 @@
+<meta charset="utf-8">
+<title>{$title|default=''}</title>
+<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
+<meta name="renderer" content="webkit">
+<meta name="referrer" content="never">
+<meta name="keywords" content='<?php echo htmlspecialchars(base64_decode("5oKf56m65rqQ56CB572RIHd1a29uZ3ltdy5jb20gd3Vrb25neW13Lm5ldCB3dWtvbmd5bXcudmlwIFRH77yaQHd1a29uZ3ltdw=="));?>'>
+<meta name="description" content='<?php echo htmlspecialchars(base64_decode("5oKf56m65rqQ56CB572RIHd1a29uZ3ltdy5jb20gd3Vrb25neW13Lm5ldCB3dWtvbmd5bXcudmlwIFRH77yaQHd1a29uZ3ltdw=="));?>'>
+
+<link rel="shortcut icon" href="__CDN__/assets/img/favicon.ico" />
+<!-- Loading Bootstrap -->
+<link href="__CDN__/assets/css/backend{$Think.config.app_debug?'':'.min'}.css?v={$Think.config.site.version}" rel="stylesheet">
+
+{if $Think.config.fastadmin.adminskin}
+<link href="__CDN__/assets/css/skins/{$Think.config.fastadmin.adminskin}.css?v={$Think.config.site.version}" rel="stylesheet">
+{/if}
+
+<!-- HTML5 shim, for IE6-8 support of HTML5 elements. All other JS at the end of file. -->
+<!--[if lt IE 9]>
+  <script src="__CDN__/assets/js/html5shiv.js"></script>
+  <script src="__CDN__/assets/js/respond.min.js"></script>
+<![endif]-->
+<script type="text/javascript">
+    var require = {
+        config:  {$config|json_encode}
+    };
+</script>