There isn't one atm. gitworkshop is a web client. There is an andriod build using capacitor. I could create an electron build if you like? I see you are a nixos user so you might not find that satifying.
The ngit cli is available cross platform and can be installed via the nix flake
ngit documentation
Install ngit | ngit
Install ngit and git-remote-nostr on macOS, Linux, Windows, or NixOS.