University IP rules are usually quite strict. If your company has anything to do with your research they'll come knocking for royalties. You should also check at what level you're allowed to do outside work, in some places grad students aren't allowed to consult for example.
While I was a postdoc I consulted for the company I used to work for sometimes. I agreed it with the University IP office and they were happy under the proviso that no institutional resources were used and it didn't affect my work any more than I declared it would.
So technically are you allowed to? The short answer is probably not with a provided machine, but you could check with your university IP people - they exist. On the other hand lots of universities run entrepreneur programs for grad students so it would be hard to see how they'd complain if you used a university supplied machine for that. They might expect a cut if you do though. In theory most universities have all sorts or rules about releasing open source software too, but I don't know anyone who's ever really followed those.
I really doubt the IT department secured and vetted a Mac. Most likely they inventoried it and gave it a sticker. If in doubt install Little Snitch and see if it phones home, but unless you're using the institution VPN I doubt they can track anything. Unlike Windows where you may have to use an institutional sign in, I think it would be obvious if such a system was on your laptop.
If you drop out of school to pursue it then they're going to ask for the laptop back at least.
The practical answer is I doubt they would know, check or even consider pursuing anything unless you really made bank. And at that point you can afford a legal team.