Docker image for one-command demo (Docker 一键体验)

[Essential1220]

Provide a Dockerfile and docker-compose.yml so new users can try the framework without building from source or downloading CTP SDK.

Scope

• Multi-stage Dockerfile (build + runtime)
• Bundle a synthetic tick generator (FakeMdGateway) for zero-dependency demo
• docker-compose up → engine starts with paper-trading + WebUI on :9090
• No CTP SDK or SimNow account needed for the demo

Tasks

• Dockerfile (Ubuntu 24.04, GCC 13, multi-stage)
• docker-compose.yml with synthetic data mode
• Update QUICKSTART with Docker instructions
• CI: build Docker image on push (optional)