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/js/event.js

@@ -0,0 +1,20 @@
+var Event = {
+  EVENT: {},
+  emit (eventName, resp) {
+    if (this.EVENT[eventName] && Object.prototype.toString.call(this.EVENT[eventName]) === "[object Array]") {
+      for (let i = 0, fn; fn = this.EVENT[eventName][i++];) {
+        fn(resp)
+      }
+    }
+  },
+  on (name, fn) {
+    if (this.EVENT[name] && Object.prototype.toString.call(this.EVENT[name]) === "[object Array]") {
+      this.EVENT[name].push(fn)
+    } else {
+      this.EVENT[name] = [fn]
+    }
+  },
+  off (name) {
+    this.EVENT[name] = null
+  }
+}