Ah, possibly - the way I think about Show HN is it's for links to a codebase or demo app. There is a demo app linked in this article but it's not the link posted to HN. The Guidelines explicitly mention "blog posts" as not Show HN - https://news.ycombinator.com/showhn.html - but they also say that's because they "can't be tried out". Grey area? Happy to do whatever precedent suggests.
Cool! I'm also not 100% sure, have only done a handful of posts. I would definitely put "Show HN" on a link to the demo app or the Github repo - and wait for the mods to correct me :D
