While skimming over the repo, I am seeing a couple of warnings that indicate leaking abstraction/boundaries :
* there are imports for Spring in the domain code (is Spring part of your domain?)
* you are using a mock framework in some domain tests
Also I am not sure I understand the "domain" and "ddd" packages. I am a huge supporter of splitting a "domain" package from a "application" package like you did, but then not sure where the ddd stands