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

composer.json

@@ -0,0 +1,40 @@
+{
+    "name": "karsonzhang/fastadmin",
+    "description": "the fastest admin framework",
+    "type": "project",
+    "keywords": [
+        "fastadmin",
+        "thinkphp"
+    ],
+    "homepage": "https://www.fastadmin.net/",
+    "license": "Apache-2.0",
+    "authors": [
+        {
+            "name": "Karson",
+            "email": "karson@fastadmin.net"
+        }
+    ],
+    "require": {
+        "php": ">=7.0.0",
+        "topthink/framework": "~5.0.24",
+        "topthink/think-captcha": "^1.0",
+        "phpmailer/phpmailer": "~6.1.6",
+        "karsonzhang/fastadmin-addons": "~1.2.4",
+        "overtrue/pinyin": "~3.0",
+        "phpoffice/phpspreadsheet": "^1.2",
+        "overtrue/wechat": "4.2.11",
+        "nelexa/zip": "^3.3",
+        "symfony/var-exporter": "^4.4.13",
+        "ext-json": "*",
+        "ext-curl": "*",
+        "ext-pdo": "*",
+        "workerman/workerman": "^4.0",
+        "telesign/telesign": "2.2",
+        "topthink/think-queue": "1.1.6",
+        "alibabacloud/client": "^1.5",
+        "tencentcloud/tencentcloud-sdk-php": "^3.0"
+    },
+    "config": {
+        "preferred-install": "dist"
+    }
+}