Add Docker deployment as the recommended production setup.

Include Dockerfile, docker-compose on port 3130, npm mirror config, deploy scripts, and DOCKER.md; keep PM2 docs as fallback.

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -13,7 +13,7 @@ OPENAI_BASE_URL=https://op.bz121.com/v1
 # AI 模型
 OPENAI_MODEL=huihui_ai/gemma-4-abliterated:e4b
 
-# 服务端口（生产 PM2 默认 3130；本地 dev 仍用 3000）
+# 服务端口（Docker / PM2 默认 3130；本地 dev 仍用 3000）
 PORT=3130
 
 # 运行环境