Putting app idea/design on portfolio vs working on it in stealth? [closed]

I'm a UX/UI designer and recently started looking for a new job. I'd been working on an app idea on the side and already got pretty far with the whole design and have a prototype. A developer friend also wanted to partner with me and we've started building the actual product.

I was originally just going to put it as one of my projects on my portfolio while I job hunt. I have a couple other work/side projects, but none of them compare in the level of enthusiasm and passion I have for this one, so it would be a strong case study to use in interviews.

However, my developer friend mentioned he was concerned if I made the design public, that makes it pretty easy for anyone to steal since they would not only have the idea but also basically the blueprints that I showcase in my portfolio. I've never ventured into actually building/launching my own mobile app and wanted to see if anyone has experience with this and advice on the best path forward -

1) Just put it on my portfolio and continue with job hunt, and deal with it later if someone else tries stealing/developing the app (is the risk high or low?)

2) Leave the app off my portfolio and create some new project ideas for my portfolio instead

3) If I'm going to be getting the app developed, commit to that fully instead of job hunting

4) Some other option?