OpenAI Codex CLI support mcp servers.

• read the documentation at https://github.com/openai/codex/blob/main/codex-rs/config.md#mcp_servers
• update the codex agentic engine (codex_engine.go) to support MCPs and generate the proper toml configuration file
• also set history to false (https://github.com/openai/codex/blob/main/codex-rs/config.md#history)