If you used Github as a simple remote repository and nothing around (CI, issues, ...), you can also setup a simple bare git repository on a server to use a your remote and a backup. There is nothing special to do once you can log with SSH into the server.
I very recently did that for my personal projects.
Unfortunately, JetBrains uses only american models for both the AI assistant and Junie:
https://www.jetbrains.com/help/ai-assistant/supported-llms.html
https://www.jetbrains.com/help/junie/models.html
It is possible to connect the AI assistant to other models, but not Junie. There are a few issues requesting the integration of Codestral in the Jetbrains issue tracker (https://youtrack.jetbrains.com/issue/JBAI-16480/Mistral-AI-integration), but with no success yet. You can go upvote it if you have a Jetbrains account.