Bold the currently checked-out branch

I think this would be good for clarity, on top of the "head" icon. Example from Fork:

<img width="357" height="478" alt="Image" src="https://github.com/user-attachments/assets/c4d732b0-02b1-493d-a921-03e0e9e6006b" />

Thank you for the excellent work!