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/component-animations.less

@@ -0,0 +1,36 @@
+// stylelint-disable selector-no-qualifying-type
+
+//
+// Component animations
+// --------------------------------------------------
+
+// Heads up!
+//
+// We don't use the `.opacity()` mixin here since it causes a bug with text
+// fields in IE7-8. Source: https://github.com/twbs/bootstrap/pull/3552.
+
+.fade {
+  opacity: 0;
+  .transition(opacity .15s linear);
+
+  &.in {
+    opacity: 1;
+  }
+}
+
+.collapse {
+  display: none;
+
+  &.in      { display: block; }
+  tr&.in    { display: table-row; }
+  tbody&.in { display: table-row-group; }
+}
+
+.collapsing {
+  position: relative;
+  height: 0;
+  overflow: hidden;
+  .transition-property(~"height, visibility");
+  .transition-duration(.35s);
+  .transition-timing-function(ease);
+}