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/fastadmin-addtabs/.bower.json

@@ -0,0 +1,14 @@
+{
+  "name": "fastadmin-addtabs",
+  "homepage": "https://github.com/karsonzhang/jquery-addtabs",
+  "version": "1.0.5",
+  "_release": "1.0.5",
+  "_resolution": {
+    "type": "version",
+    "tag": "v1.0.5",
+    "commit": "b3b3bb0eced30be1f4927886b155b679dbbb5e5e"
+  },
+  "_source": "https://github.com/karsonzhang/jquery-addtabs.git",
+  "_target": "~1.0.5",
+  "_originalSource": "fastadmin-addtabs"
+}