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/grid.less

@@ -0,0 +1,94 @@
+//
+// Grid system
+// --------------------------------------------------
+
+
+// Container widths
+//
+// Set the container width, and override it for fixed navbars in media queries.
+
+.container {
+  .container-fixed();
+
+  @media (min-width: @screen-sm-min) {
+    width: @container-sm;
+  }
+  @media (min-width: @screen-md-min) {
+    width: @container-md;
+  }
+  @media (min-width: @screen-lg-min) {
+    width: @container-lg;
+  }
+}
+
+
+// Fluid container
+//
+// Utilizes the mixin meant for fixed width containers, but without any defined
+// width for fluid, full width layouts.
+
+.container-fluid {
+  .container-fixed();
+}
+
+
+// Row
+//
+// Rows contain and clear the floats of your columns.
+
+.row {
+  .make-row();
+}
+
+.row-no-gutters {
+  margin-right: 0;
+  margin-left: 0;
+
+  [class*="col-"] {
+    padding-right: 0;
+    padding-left: 0;
+  }
+}
+
+
+// Columns
+//
+// Common styles for small and large grid columns
+
+.make-grid-columns();
+
+
+// Extra small grid
+//
+// Columns, offsets, pushes, and pulls for extra small devices like
+// smartphones.
+
+.make-grid(xs);
+
+
+// Small grid
+//
+// Columns, offsets, pushes, and pulls for the small device range, from phones
+// to tablets.
+
+@media (min-width: @screen-sm-min) {
+  .make-grid(sm);
+}
+
+
+// Medium grid
+//
+// Columns, offsets, pushes, and pulls for the desktop device range.
+
+@media (min-width: @screen-md-min) {
+  .make-grid(md);
+}
+
+
+// Large grid
+//
+// Columns, offsets, pushes, and pulls for the large desktop device range.
+
+@media (min-width: @screen-lg-min) {
+  .make-grid(lg);
+}