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/font-awesome/scss/_animated.scss

@@ -0,0 +1,34 @@
+// Spinning Icons
+// --------------------------
+
+.#{$fa-css-prefix}-spin {
+  -webkit-animation: fa-spin 2s infinite linear;
+          animation: fa-spin 2s infinite linear;
+}
+
+.#{$fa-css-prefix}-pulse {
+  -webkit-animation: fa-spin 1s infinite steps(8);
+          animation: fa-spin 1s infinite steps(8);
+}
+
+@-webkit-keyframes fa-spin {
+  0% {
+    -webkit-transform: rotate(0deg);
+            transform: rotate(0deg);
+  }
+  100% {
+    -webkit-transform: rotate(359deg);
+            transform: rotate(359deg);
+  }
+}
+
+@keyframes fa-spin {
+  0% {
+    -webkit-transform: rotate(0deg);
+            transform: rotate(0deg);
+  }
+  100% {
+    -webkit-transform: rotate(359deg);
+            transform: rotate(359deg);
+  }
+}