[FEATURE] Allow hiding/blocklisting models from the model dropdown

What feature would you like to see?

It would be great to have a way to hide or blocklist certain models from appearing in the model dropdown in the Codex desktop app. Not every model is relevant for every user, and the dropdown gets cluttered with models you'd never pick (e.g., GPT-5.1-Codex-Mini).

<img width="173" height="252" alt="Image" src="https://github.com/user-attachments/assets/7b05eb43-a43c-49eb-90c7-845ace09c51e" />

A simple configuration option — either in settings or a config file — where you can specify a list of models to exclude from the dropdown would go a long way toward keeping the UI clean and reducing selection friction.

Something like:

{
  "hiddenModels": ["GPT-5.1-Codex-Mini", "..."]
}

Or alternatively, an allowlist approach where you can pin only the models you actually use.

Additional information

• Codex CLI version: codex-cli 0.106.0
• Platform: macOS v26.3.1