DSA key support was removed in OpenSSH 10.0

[City-busz]

The DSA signature algorithm is deprecated since 2015, and the support is removed in OpenSSH 10.0, which was released on 2025-04-09:
https://www.openssh.com/txt/release-10.0

This means that Sugar fails to generate SSH keys with unknown key type dsa error.

Replacing dsa with rsa at:

sugar/src/jarabe/intro/window.py

Line 83 in 892178a

cmd = "ssh-keygen -q -t dsa -f %s -C '' -N ''" % (keypath, )

and replacing ssh-dss with ssh-rsa at:
https://github.com/sugarlabs/sugar-toolkit-gtk3/blob/216a5daa34bf84938e1cebfa6135c1d02ff51c5d/src/sugar3/profile.py#L90

could solve the problem.