Suggestion: URL endpoint for easy certificate sharing
First of all, thank you for starting this project. I admittedly haven't had much time yet to really look around and play with it, but looks like a very handy tool to have!
One quick suggestion that I'd already like to make is one for convenience and with some luck one that is relatively easy to implement:
When one wants to play around with mobile devices, you need to somehow get the certificate to them. It would be convenient if Hetty had a special URL endpoint like "/ssl" or "/getssl" like Charles Proxy to download the generated/configured certificate. You'd be able to grab your phone/tablet, browse to that built-in link, install the certificate and be on your traffic-inspecting way!
I think that's the same way, Burp also implements it. Sounds reasonable.