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/less/fastadmin/table.less

@@ -0,0 +1,71 @@
+/*
+ * Component: Table
+ * ----------------
+ */
+
+.table {
+  //Cells
+  > thead,
+  > tbody,
+  > tfoot {
+    > tr {
+      > th,
+      > td {
+        border-top: 1px solid @box-border-color;
+      }
+    }
+  }
+  //thead cells
+  > thead > tr > th {
+    border-bottom: 2px solid @box-border-color;
+  }
+  //progress bars in tables
+  tr td .progress {
+    margin-top: 5px;
+  }
+}
+
+//Bordered Table
+.table-bordered {
+  border: 1px solid @box-border-color;
+  > thead,
+  > tbody,
+  > tfoot {
+    > tr {
+      > th,
+      > td {
+        border: 1px solid @box-border-color;
+      }
+    }
+  }
+  > thead > tr {
+    > th,
+    > td {
+      border-bottom-width: 2px;
+    }
+  }
+}
+
+.table.no-border {
+  &,
+  td,
+  th {
+    border: 0;
+  }
+}
+
+/* .text-center in tables */
+table.text-center {
+  &, td, th {
+    text-align: center;
+  }
+}
+
+.table.align {
+  th {
+    text-align: left;
+  }
+  td {
+    text-align: right;
+  }
+}