how can I do this, without renaming it to 

transaction:transaction-contract

?

I'm not sure if you are able to do that without renaming the project, but you can rename your Gradle project via

settings.gradle

without renaming anything in the filesystem. I've done the same thing here: https://github.com/inkremental/inkremental/blob/3fe43fac04b4074f1cece7a18aa43450050de59e/settings.gradle.kts#L34-L40

does intellij give you the full dashed name in brackets next to your short folder name?

Yep