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/addons/example/css/common.css

@@ -0,0 +1,106 @@
+html,
+body {
+    height: 100%;
+}
+
+body {
+    padding-top: 50px; /* Required padding for .navbar-fixed-top. Remove if using .navbar-static-top. Change if height of navigation changes. */
+    -webkit-font-smoothing: antialiased;
+    -moz-osx-font-smoothing: grayscale;
+    font-family: 'Source Sans Pro', 'Helvetica Neue', Helvetica, Arial, sans-serif;
+}
+
+.img-addon {
+    margin-bottom: 10px;
+    width:100%;
+}
+
+.img-hover:hover {
+    opacity: 0.8;
+}
+
+.display-1 {
+    font-size:44px;
+}
+.display-4 {
+    font-size:24px;
+    line-height:32px;
+}
+
+/* Home Page Carousel */
+
+header.carousel {
+    height: 50%;
+}
+
+header.carousel .item,
+header.carousel .item.active,
+header.carousel .carousel-inner {
+    height: 100%;
+}
+
+header.carousel .fill {
+    width: 100%;
+    height: 100%;
+}
+
+/* 404 Page Styles */
+
+.error-404 {
+    font-size: 100px;
+}
+
+/* Pricing Page Styles */
+
+.price {
+    display: block;
+    font-size: 50px;
+    line-height: 50px;
+}
+
+.price sup {
+    top: -20px;
+    left: 2px;
+    font-size: 20px;
+}
+
+.period {
+    display: block;
+    font-style: italic;
+}
+
+/* Footer Styles */
+
+footer {
+    margin: 50px 0;
+}
+
+/* Responsive Styles */
+
+@media(max-width:991px) {
+    .customer-img,
+    .img-related {
+        margin-bottom: 30px;
+    }
+}
+
+@media(max-width:767px) {
+    .img-addon {
+        margin-bottom: 15px;
+    }
+
+    header.carousel .carousel {
+        height: 70%;
+    }
+}
+.carousel-body {
+    position:absolute;
+    width: 100%;
+    top:25%;
+    text-align:center;
+    color:#fff;
+}
+
+.addonlist a > p{
+    margin-bottom:15px;
+}