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/command/Crud/stubs/html/heading-html.stub

@@ -0,0 +1,10 @@
+
+    <div class="panel-heading">
+        {:build_heading(null,FALSE)}
+        <ul class="nav nav-tabs" data-field="{%field%}">
+            <li class="{:$Think.get.{%field%} === null ? 'active' : ''}"><a href="#t-all" data-value="" data-toggle="tab">{:__('All')}</a></li>
+            {foreach name="{%fieldName%}List" item="vo"}
+            <li class="{:$Think.get.{%field%} === (string)$key ? 'active' : ''}"><a href="#t-{$key}" data-value="{$key}" data-toggle="tab">{$vo}</a></li>
+            {/foreach}
+        </ul>
+    </div>