Re "stage 2: persistent sessions", iTerm2 already does this. The PTYs are owned by background processes independent of the GUI application. So iTerm2 can upgrade the application without interrupting the running terminal sessions.
this is really cool omg! i didn't know that, i'll do some research.
one of the strange things to me about the terminal landscape is how little knowledge sharing there is compared to other domains i'm familiar with. iTerm has a bunch of things no one else has; kitty influenced wezterm but otherwise no one else seems to have valued reflection; there's a whole bunch of extensions to ANSI escapes but most of them are non-standard and mutually incompatible. it's weird. if i compare to something like build systems, there's a lot more cross-pollination of ideas there.
If we are going to broaden this to Screen and its "TUI" style features, then the most complete effort at a programmable TUI in the Linux space I've seen is `desktop-tui`.
