Feature request: Don’t follow output if last line not visible

First of all, I <3 blink, thanks a bunch!

I’d love for blink to follow the terminal output _if and only if_ I’m looking at the bottom of the screen (last printed line). I often scroll up to look at the output of previous commands while some other command is still running; in blink, whenever the (running) command outputs a line, I’ll be taken back to that (new) line and I have to scroll up again.

Start by reproducing this in Blink on iOS or iPadOS: run a command that emits output, scroll above the last line, and observe whether new output changes the view. Done means output follows only while the last printed line is visible, while scrolling up leaves the viewport in place.

Written by the indexing model from the issue text.