Agent co author | add specific model information to commit

Testing #297204

Currently the commit only shows `Copilot` as a co author, but not the specific model used in the edit. It would be great to see something like `Claude Opus 4.6 | 24 Feb`. 

<img width="512" height="200" alt="Image" src="https://github.com/user-attachments/assets/ac2d9525-959d-4db6-bae5-bd142b7b2339" />
