Russia already had an agreement with Ukraine to respect the 1994 boundaries of Ukraine - the Budapest Memorandum.
It’s like if someone promised not to burgle your house. Then they burgle your house anyway - but promise they’ll stop burgling for real if you promise to let them keep the stuff they already took, and throw in some more, and promise to never to lock your doors.
Self-hosted Gitea or Forgejo. It’s pretty easy to host, and if you’ve got a reliable Internet connection and an always on computer, you can host it from home without too much effort.