修复：补充 Docker COS 凭证配置，修复截图代理 404 问题

- docker-compose.yml 添加 COS_SECRET_ID/KEY/REGION/BUCKET 环境变量透传
- docker/.env 填入腾讯云 COS 凭证和截图回调地址
- AiRoiController 移除多余 @GetMapping 注解，消除 Spring 双注解警告

根因：容器未传入 COS 凭证 → CosUtil 初始化跳过 → proxyScreenshotImage 返回 null → 404

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/docker-compose.yml

@@ -133,6 +133,15 @@ services:
       RecordSip: ${RecordSip}
       RecordPushLive: ${RecordPushLive}
 
+      # COS 截图代理
+      COS_SECRET_ID: ${COS_SECRET_ID:}
+      COS_SECRET_KEY: ${COS_SECRET_KEY:}
+      COS_REGION: ${COS_REGION:ap-beijing}
+      COS_BUCKET: ${COS_BUCKET:}
+
+      # AI 截图回调地址
+      AI_SCREENSHOT_CALLBACK_URL: ${AI_SCREENSHOT_CALLBACK_URL:}
+
   polaris-nginx:
     # 显式指定构建上下文和Dockerfile路径
     build: