Reimplement Windows shortcut creation in CGo

[leafo]

Other tasks:

• remove husk and co (archive the repo)
• make sure the shortcut has app id set to io.itch.itch so that desktop notifications show the app's full name and not the app id.
• test installing the app on a fresh windows vm to verify

[leafo]

Signed builds here: https://github.com/itchio/itch-setup/actions/runs/21848048508