Add a field to modify unresponsiveness detection timeout

[ProgramCrafter]

Problem

Unresponsiveness detector is bugged, so that accidentally clicking to force quit a process which already stopped crashes the whole session (elementary/gala#2453).

I also think a configurable timeout is generally useful, for already-existing apps which are known to have long computations.

Proposal

Create a field, interface for gsettings set org.gnome.mutter check-alive-timeout <XXX> (in the command, 0 stands for "do not even check if app responds").

Prior Art (Optional)

No response

[danirabbit]

Force quitting an app definitely shouldn't crash the session, but this seems like a foot gun. I don't think it's a good idea to disable fail safe features because some apps are known to have buggy behavior and it's annoying that those apps are buggy. The apps should be fixed

[ProgramCrafter]

The apps should be fixed

To be frank, some apps are outside of anyone's control here to fix, and one may still wish to use them.

That's not so grim in my experience though, just a wishlist; I mainly saw unresponsive apps with a several-minutes-worth IO queue on my disk drive.