codex cannot start mcp without "--quiet" argument

[Tonghua-Li]

Your Redot version:
26.1
Issue description:
codex cannot start mcp without "--quiet" argument

URL to the documentation page (if already existing):
https://docs.redotengine.org/tutorials/editor/mcp_server

I am going to make a PR to add this into doc.

[mcp_servers.redot]
args = ["/path/to/redot/redot.linuxbsd.editor.x86_64.mono", "--headless", "--mcp-server", "--quiet", "--path", "/abs/to/game/project"]
command = "/usr/bin/env"
enabled = true