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/jquery/bower.json

@@ -0,0 +1,14 @@
+{
+  "name": "jquery",
+  "main": "dist/jquery.js",
+  "license": "MIT",
+  "ignore": [
+    "package.json"
+  ],
+  "keywords": [
+    "jquery",
+    "javascript",
+    "browser",
+    "library"
+  ]
+}