fix(trading-service): 添加做市商钱包环境变量，修复地址未配置问题

FUSDT/EUSDT_MARKET_MAKER_ADDRESS 和 USERNAME 只传给了
mining-blockchain-service，但 trading-service 初始化时也需要
读取这些变量写入数据库，导致前端显示"做市商钱包地址未配置"。

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/docker-compose.2.0.yml

@@ -116,6 +116,11 @@ services:
       MINING_ADMIN_SERVICE_URL: http://mining-admin-service:3023
       # JWT 配置 (与 auth-service 共享密钥以验证 token)
       JWT_SECRET: ${JWT_SECRET:-your-jwt-secret-change-in-production}
+      # 做市商钱包 (MPC) - 初始化时写入数据库
+      FUSDT_MARKET_MAKER_USERNAME: ${FUSDT_MARKET_MAKER_USERNAME:-}
+      FUSDT_MARKET_MAKER_ADDRESS: ${FUSDT_MARKET_MAKER_ADDRESS:-}
+      EUSDT_MARKET_MAKER_USERNAME: ${EUSDT_MARKET_MAKER_USERNAME:-}
+      EUSDT_MARKET_MAKER_ADDRESS: ${EUSDT_MARKET_MAKER_ADDRESS:-}
     ports:
       - "3022:3022"
     healthcheck: