feat: implement OpenAI-compatible Realtime API with authentication and management features

- Added support for public Realtime API, including new routes for managing API keys and handling WebRTC connections.
- Introduced RealtimeApiKey model and associated CRUD operations for admin management of API keys.
- Implemented authentication mechanisms for API keys and client secrets.
- Enhanced environment configuration with new secrets for Realtime API.
- Created OpenAIRealtime session management and event processing for real-time interactions.
- Updated schemas and settings to accommodate new features and ensure compatibility with existing systems.

docs-developer/index.mdx

@@ -40,6 +40,10 @@ make db-seed
 
 保存后，从助手详情页打开语音预览即可测试。
 
+## 4. 对接 Realtime 协议
+
+- [Realtime 兼容协议设计](/realtime-protocol)：了解后端提供的 OpenAI Realtime 兼容 WebRTC、WebSocket、鉴权与 Interactive Media 扩展协议。
+
 <Note>
 浏览器麦克风仅在 localhost 或 HTTPS 下可用。局域网、远程环境请按仓库中的 `deploy/README.md` 配置 HTTPS 与 TURN。
 </Note>