Custom model support

Hi,

I really like the integration and output into Gitlab, works like a charm.
The one thing that seems to be missing (or perhaps I'm setting up the environment incorrectly) are custom models.
We are happily running Junie local models (through ~/.junie/models/xxxx.json) but whatever I do (global models, through global config, project model locations or environment variables) only the built-in models are available.

Would it be feasible to either add/ support it, or can you point me into the right direction for setup.
Happy to extend the cookbook / guides in case we are able to support it.

Thanks!

No file, test, or code entry point is named. Start by locating the configuration and model-discovery paths, then reproduce the difference between built-in models and ~/.junie/models/xxxx.json or the mentioned global, project, and environment-variable settings. Done means custom Junie models are available, or the supported setup is documented in the cookbook or guides.

Written by the indexing model from the issue text.