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/jquery-slimscroll/examples/style.css

@@ -0,0 +1,13 @@
+body { font-family:Verdana,sans-serif; font-size:12px; color:#000; background:#111; }
+h1 { font-size:20px; margin:0 }
+h2 { font-size:10px; margin:0 }
+p { margin:5px 0; font-size:12px; }
+pre.prettyprint { padding:15px; border:1px solid #eee; border-radius:5px; background:#eee; border-bottom:3px solid; }
+.examples { border-radius:20px; background:#fff; padding:15px;
+  margin:0 150px 0 0; border-collapse: collapse; border:1px solid #000; }
+.slimScrollDiv { border:1px solid #eee; }
+#nav { position:fixed; top:0; left:0; background:#fff; padding:15px; border-radius:20px; width:200px; }
+#nav ul { list-style-type:square; list-style-position:inside; margin:20px 0 0 0; padding:0; }
+#nav a { text-decoration:none; color:#000; }
+#nav a:hover { text-decoration: underline }
+#git-fork img { position:fixed; top:0; right:0; border:0; z-index:999; }