CodeLab Feedback - Build an animated responsive app layout with Material 3

RE: https://codelabs.developers.google.com/codelabs/flutter-animated-responsive-layout#8

I love this codelab and recommend it all the time when people ask about how to do responsive layouts in Flutter. I do think it comes up just a bit short though. It would be more complete if you added some steps to show how to handle the list/detail with respect to navigation when clicking an item in the list. As is you stop short and people have a hard time knowing what to do when the users clicks/taps an item in the list. Do you navigate to the details? Does it just show up (it does now, but only when the window is wide enough). What about when you are on a phone, how do you show the details and a back button or something like that, but then only do that when the window is small enough too.

Hope this makes sense, happy to provide more info if needed.

Start with the linked Flutter codelab, especially section 8, and review how the current list/detail interaction behaves at wide and narrow window sizes. Add guidance for selecting an item, showing details on phones, and providing back navigation when appropriate. Done means the codelab explains both responsive cases clearly.

Written by the indexing model from the issue text.