Yes, Arctic does support URL schemes. I made it as simple as possible, no need to grab the post_id or comment_id. Just simply pass it the URL to any post, comment, user, or community. This also works for most MBin URLS. The url scheme for Arctic is arctic://open-in?url={content_url}
for example to open this post you'd use arctic://open-url?url=https://lemmy.world/post/25543739
Tapestry looks interesting, it's been a while since I've found any rss readers that I actually enjoyed using, I'll have to check that out. I definitely like that it supports URL schemes rather than opening in a browser.
Looking at the Tapestry documentation, you will likely want to use the __URL_ENCODED__
substitution variable for Arctic eg: arctic://open-in?url=__URL_ENCODED__
I should probably add a section in Arctic settings to list the supported URL schemes. Right now they are only listed in the Changelog, and they are all buried.
If you have any issues with it feel free to let me know know and I'll help you out, or add new schemes if needed.
Glad you're enjoying Arctic!!