[Lizard]

You cannot put an action or action group directly into a folder.

A single action list is a type of project. So a folder could hold a single action list. That is what my Household folder and Sporadic Household list show.

Going back to the original poster's example, one could make House a single action list project, with action groups for Finish Shelf Lining and Unpacking, and an action for "Route the ethernet cable".

Perhaps I'm not understanding your suggestion?