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/require-css/package.json

@@ -0,0 +1,10 @@
+{
+  "name": "require-css",
+  "version": "0.1.10",
+  "volo": {
+    "type": "directory"
+  },
+  "scripts": {
+    "test": "node test/test.js"
+  }
+}