Allow disabling individual built-in models

Feature request

I'd like to be able to disable individual built-in Command Code models from the /model menu.

Right now, ~/.commandcode/providers.json supports disabling an entire BYOK provider with "disabled": true, but there doesn't seem to be a supported way to hide or disable one specific built-in model.

I'd like a configuration option at user scope that lets me disable specific models without removing access to the rest of the catalog. This would make the model picker less cluttered and make it easier to prevent accidental selection of models I don't want to use.

Suggested behavior

• Support an allowlist or denylist for built-in model IDs.
• Apply it to the /model menu and model selection shortcuts.
• Keep the setting at user scope so it applies across projects.
• Keep the current BYOK provider-level disabled behavior unchanged.

Example

{
  "disabledModels": ["some/model-id"]
}

~/.commandcode/providers.json で表されるユーザースコープの設定から始め、次に /model メニューとモデル選択のショートカットを追跡します。組み込みモデル ID とプロバイダーレベルで無効化された設定がどのように読み込まれ、フィルタリングされるかを確認します。ユーザーがプロジェクト間で選択した組み込みモデルを無効化でき、既存の BYOK プロバイダーの動作が変わらない状態になれば完了です。