By "the app," do you mean the Hubitat mobile app? If so, unlikely. But the forum software is Discourse, and that has an app. I haven't looked into notifications much (it's a very thin wrapper around the website, from all I can tell, and I just prefer the website ), but maybe there would be an option in that app to do what you want. I know even the website supports notifications on desktop, so perhaps that would work on mobile, too.
It would certainly be possible. I looked into it ages ago and while the generation of an API key that I found was quite dubious, it was easy to make HTTP calls to the Community and get the data behind what you see on the Community page. (Dubiosity not related in any way to Hubitat, more what I was prepared to use to get something working at the time, I'm sure there is a more appropriate way to register an api key).
Basically everything you see is json, a common data format used nowadays, particularly in drivers on the Community. As long as you get an API key you can get access to almost all the same data you see presented on the web page.
Always been in the back of my mind as another use case for my avatar driver....
I was able to combine notifications from different "communities" into the same Discourse app, but would like the option to run automations when notifications appear.
I think I'll setup a thread to develop this.... Been on my list for a while now... Deserves to act as another distraction from the other projects I have committed to.... Just need to find a neater way of generating the API key than what I used originally....
I'm expecting this to be my guide for this (admin settings pending...):