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"]
}

Comienza con la configuración de ámbito de usuario representada por ~/.commandcode/providers.json y, a continuación, sigue el menú /model y los atajos de selección de modelos. Comprueba cómo se cargan y filtran los IDs de modelos integrados y las configuraciones deshabilitadas a nivel de proveedor. Se considera terminado cuando un usuario puede deshabilitar modelos integrados seleccionados en distintos proyectos, mientras el comportamiento existente del proveedor BYOK permanece sin cambios.