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

addons/kefu/example/kefu_uni/pages.json

@@ -0,0 +1,24 @@
+{
+	"pages": [ //pages数组中第一项表示应用启动页，参考：https://uniapp.dcloud.io/collocation/pages
+		{
+		    "path" : "pages/kefu/index",
+		    "style" : {
+				"navigationBarTitleText":"在线客服",
+				"navigationBarTextStyle": "black"
+			}
+		},
+		{
+			"path": "pages/kefu/kefu",
+			"style": {
+				"navigationBarTitleText":"链接中...",
+				"navigationBarTextStyle": "black"
+			}
+		}
+    ],
+	"globalStyle": {
+		"navigationBarTextStyle": "black",
+		"navigationBarTitleText": "在线客服",
+		"navigationBarBackgroundColor": "#F8F8F8",
+		"backgroundColor": "#F8F8F8"
+	}
+}