As luck would have it, the day after this beta was released, Rails released rc1 of Rails 7.2.0: Ruby on Rails — Rails 7.2 release candidate 1: Better production defaults, Dev containers, new guides design, and more!
Rerunning the scenario from the book, the only relevant difference I have found is that scaffold generated views use form.textarea instead of form.text_area. Both work, and the next beta update will update the code samples to match what Rails currently generates.
The Dockerfile has been updated to reference thruster. I’m investigating this change.