[FEATURE]: Disabling specific models through opencode.json #3411

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Hi! First of all, thank you for your work on this tool :)

We're using Opencode as an interface for an LLM based workflow, that people install on their machines, along with a config file. We set the model to a default tested model that we verified works fine, but this still leaves the possibility of someone changing the model by accident open.

I would like to request a feature that would allow to disable specific models in opencode.json, so they don't show up in the model list.
This is useful not only in the usecase I described above, but also when you have a provider that supplies a bunch of models you don't care about (like Copilot providing Claude 3.5 etc.). This feature would allow you to have only the models you're interested in using displayed on the list.

Thanks!