Dang, I was hoping this might be something cool about graphs in the Lean language/theorem prover.

Same here - maybe the HN post should be retitled to "Lean Manufacturing and Graph Theory."

Same! It's a field I mess around with a lot as an amateur and was hoping to get a better hang on it for a personal project.

I was expecting that too. :(

I wouldn’t use a tree to depict a DAG.

While technically true, it’s not the first thing that comes to mind when you think about DAGs. And in the context of the Product Management, I would’ve split it into Trees and DAGs.

E.g. a tree is when you recursively subdivide tasks into smaller ones, where at the leaves you have a ready for execution tickets. While DAGs are more like workflows or pipelines.