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

public/assets/libs/art-template/loader/index.js

@@ -0,0 +1,18 @@
+var template = require('art-template/dist/template');
+
+module.exports = function(source) {
+    this.cacheable && this.cacheable()
+
+    var ANONYMOUS_RE = /^function\s+anonymous/
+
+    template.onerror = function(e) {
+        var message = 'Template Error\n\n';
+        for (var name in e) {
+            message += '<' + name + '>\n' + e[name] + '\n\n';
+        }
+        throw new SyntaxError(message)
+    }
+
+    var render = template.compile(source, {}).toString().replace(ANONYMOUS_RE, 'function');
+    return 'module.exports = require("art-template/loader/runtime")(' + render + ');';
+}