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

nbproject/project.properties

@@ -0,0 +1,7 @@
+include.path=${php.global.include.path}
+php.version=PHP_70
+source.encoding=UTF-8
+src.dir=.
+tags.asp=false
+tags.short=false
+web.root=.

nbproject/project.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://www.netbeans.org/ns/project/1">
+    <type>org.netbeans.modules.php.project</type>
+    <configuration>
+        <data xmlns="http://www.netbeans.org/ns/php-project/1">
+            <name>196-5</name>
+        </data>
+    </configuration>
+</project>