Shade, temporary cover crop advice needed

Hi all.  I wonder if anyone might have any ideas for a little conundrum I have.
Our property is small, under a third of an acre, with a house plopped right in the middle, and it’s mostly shade. Our back yard, east facing with trees to the east on the neighboring property, has had a trampoline in one spot for a number of years. I’ve just relocated it to a different spot for aesthetic reasons. Where it was hasn’t been walked on for years, and the soil has mostly just been covered by leaves that blew underneath. There’s nothing growing there other than a bit of creeping Charlie, but it has great tilth.
I plan over the course of this and next year to have a significant expansion in the number plants back there, essentially turning it into a woodland garden, with a mix of native ornamental and edible plants. However, it’ll take time.
Does anyone have any suggestions for an easy cover crop I could throw down come spring to
A: stop undesired plants from colonizing the area
B: signal to young humans not to walk in here?

I was thinking maybe northern sea oats?
I’m in eastern Pennsylvania, USA. Zone 6 B. Bright but almost full shade.
Thanks,
Daniel

My favorite cover crop to recommend is either clover or ryegrass.

Ryegrass is the one we use the most as it dies back when the weather gets warm.

Here are some threads that you or others might find interesting:

https://permies.com/t/23764/Cover-Crop-Home-Garden-Buckwheat

https://permies.com/t/208244/Annual-Ryegrass-current-list-reasons

If you want something temporary then I'm wondering whether parsley might fit the bill? Don't laugh, but I find it grows pretty well for me, even in part shade and my climate is rather cool. It's a biennial plant, so other than possibly seeding around in the second year it shouldn't be too much of a problem, you can eat it or dry it for later, and the seeds should be easy and cheap.
For a permanent cover you could try a creeping raspberry of some kind, or maybe Cornus canadensis. Once established these can stay put - just rip them out where you want to plant other things. Another suggestion for a low growing perennial is violets - leaves and flowers are edible and they prefer a bit of shade.