By default, the Name field is not tracked in the update feeds, however, you can turn that on by going into Setup > Interface > Update Feeds > Add Fields + and adding both Project and Task Name. That won't retroactively show name changes in the update feed, but moving forward you'll be able to see who changed the name and when. The update won't show what the name was before, that may be something you have to look back in your Preview environment (if it happened within the past week). Or if you have a calculated custom field on your project custom form that pulls in the project name, since that will only update if manually recalculated.
Only users with a Plan license who have Manage permissions on the project would be able to update the name of the project, so that would limit who has the ability to do so. If there is a specific naming convention for your projects that should not be altered, you may want to consider this a training opportunity to let users know.
