This is exciting! If RDoc and RBS start playing nice, I would love to write RDoc in my .rbs files instead of my .rb files. That would make the .rbs be the full canonical documentation, without implementation details. It would also keep the ruby easier to navigate with fewer comments.

Can I use these for Rails + Stimulus apps, rather than Astro?

Glad I could inspire! If you're looking for specifics on how to do this, check out Chapter 9 of Continuous Delivery by
@davefarley77.bsky.social and @jezhumble.net. It has a whole section titled "The First Deployment."

I’d be glad to send it to you. I hope you don’t mind that I’ve read it though 😅