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/bootstrap-select/docs/custom_theme/js/base.js

@@ -0,0 +1,21 @@
+/* Highlight */
+$( document ).ready(function() {
+    hljs.initHighlightingOnLoad();
+    $('table').addClass('table table-striped table-hover');
+    $('pre').addClass('highlight');
+});
+
+$('body').scrollspy({
+    target: '.bs-sidebar',
+});
+
+$('.bs-sidebar').affix({
+  offset: {
+    top: 210
+  }
+});
+
+/* Prevent disabled links from causing a page reload */
+$("li.disabled a").click(function() {
+    event.preventDefault();
+});