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/less/path.less

@@ -0,0 +1,15 @@
+/* FONT PATH
+ * -------------------------- */
+
+@font-face {
+  font-family: 'FontAwesome';
+  src: url('@{fa-font-path}/fontawesome-webfont.eot?v=@{fa-version}');
+  src: url('@{fa-font-path}/fontawesome-webfont.eot?#iefix&v=@{fa-version}') format('embedded-opentype'),
+    url('@{fa-font-path}/fontawesome-webfont.woff2?v=@{fa-version}') format('woff2'),
+    url('@{fa-font-path}/fontawesome-webfont.woff?v=@{fa-version}') format('woff'),
+    url('@{fa-font-path}/fontawesome-webfont.ttf?v=@{fa-version}') format('truetype'),
+    url('@{fa-font-path}/fontawesome-webfont.svg?v=@{fa-version}#fontawesomeregular') format('svg');
+  // src: url('@{fa-font-path}/FontAwesome.otf') format('opentype'); // used when developing fonts
+  font-weight: normal;
+  font-style: normal;
+}