Add support for --config/-c to Typescript SDK

What feature would you like to see?

Hi, I'd like to have support for arbitrary --config/-c flags available in the SDK to provide the full power of the codex CLI exec to the SDK. I have a minimal PR implementing this in https://github.com/niteshiftdev/codex/pull/2 but happy to have this implemented however it makes sense.

Something like this would be nice:

const codex = new Codex({
  config: {
      "shell_environment_policy.inherit": "all",
      "shell_environment_policy.ignore_default_excludes": true,
      model_reasoning_effort: "low",
  }
});

Additional information

My use case is primarily being able to control knobs that are useful within our sandbox execution and the model reasoning level.