Once you've set up SSH (help.krystal.io/cpanel-advan...) on your package, you can then use git using the full path (help.krystal.io/web-hosting/...) But, actually, we really could use a detailed guide on how to set it up and get everything rolling, so thank you for asking – we'll get that sorted!
But would we get dev+ stage + prod ?
Using git on your Emerald package would only give you a repo and deployment to one directory. If you wanted dev/stage/prod, you could set up separate domains/subdomains pointing to separate directories, and then link to your branches. But it's not quite a full dev pipeline as such. Hope this helps!