I have been doing desktop applications using Qtools[0] which is relatively pleasant to work with. I have prepared a hello-world kind of Qtools project[1] that is automatically built and released into ZIP files using Travis CI. (I haven't looked at it for a while and it seems that the configuration for one of the OSes needs a bit of an update due to a change in the directory structure of SBCL releases there, but the rest works.)

I don't have much experience with web applications in Lisp, but there's some substantial tooling there and I know of people who have done that before, both client- and server-wise.

I have no experience whatsoever about Common Lisp on mobile.

[0] https://github.com/Shinmera/qtools

[1] https://github.com/phoe-trash/furcadia-post-splitter