I've been thinking about this. First step would be an API. Second step would be to either me learn Cocoa, ObjC or .NET to do this on the phones/desktops apps, etc..., or let the community do it.
Tools like React Native and Electron are pretty popular these days to build cross-platform apps and such. Since you know web stuff and I'm assuming JS, those might be a good option to explore so you could maintain them without having to learn the entire toolchain of building for various platforms
I think I'll focus my energy on creating an API first, then I'll be able to do this. I understand how important being on mobile as a native app is. I'll do it