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/less/pager.less

@@ -0,0 +1,54 @@
+//
+// Pager pagination
+// --------------------------------------------------
+
+
+.pager {
+  padding-left: 0;
+  margin: @line-height-computed 0;
+  text-align: center;
+  list-style: none;
+  &:extend(.clearfix all);
+  li {
+    display: inline;
+    > a,
+    > span {
+      display: inline-block;
+      padding: 5px 14px;
+      background-color: @pager-bg;
+      border: 1px solid @pager-border;
+      border-radius: @pager-border-radius;
+    }
+
+    > a:hover,
+    > a:focus {
+      text-decoration: none;
+      background-color: @pager-hover-bg;
+    }
+  }
+
+  .next {
+    > a,
+    > span {
+      float: right;
+    }
+  }
+
+  .previous {
+    > a,
+    > span {
+      float: left;
+    }
+  }
+
+  .disabled {
+    > a,
+    > a:hover,
+    > a:focus,
+    > span {
+      color: @pager-disabled-color;
+      cursor: @cursor-disabled;
+      background-color: @pager-bg;
+    }
+  }
+}