Re: #2, I think I was looking for something different and likely simpler than what you were thinking... The session would still be running in a codespace, I just want to be able to start on my phone, then move to my Mac, which has a nicer keyboard, and still have the codespace automatically shut down when things go idle (depending on how you have that set up, it may be that I need a dedicated app for that, or it may be I just need to VA Code remote into the codespace).
Ahh, understood. Today you can install the iPad version to your mac, not the best experience but would get you what you want. I'll do some more thinking about a more Mac OS native experience.