which begs the quotation: is there such a thing as a “firewall” for terminals?
my idea is to limit the terminal’s cpu usage so that any breach does not spread quickly in the system, and maybe limit the terminal’s network access, but leave the shell out of it. idk if the last part is possible.
And to be clear, your question is a good one. It's just that it's raised and not begged. That said, I see and hear this all the time, including by historians of philosophy who are strongly familiar with logical fallacies and their distinctions.
Begging the question isn't usually used like this these days, even if it did originate thus. The English language is used the way English speakers use it; yes, even that is quite circular, because there is no formal academy setting down rules that everyone agrees on. Institutions only teach stylistic choices. We use beg the question in exactly the way you say we shouldn't far more often than not to the point that its history is merely a bit of trivia, at least to most American English speakers; Oxford has yet to catch up, but I can't imagine the English situation is that much different than the American one.
I think that is probably excessive, a terminal is hardly as complex as a web browser.
screen or tmux (or even mosh) can essentially act as a terminal firewall, as they interpret escape sequences and maintain a virtual “screen”. Then you can sandbox their process in docker or similar.
Or if you want web browser style sandboxing maybe just using Xterm.js could work.
my idea is to limit the terminal’s cpu usage so that any breach does not spread quickly in the system, and maybe limit the terminal’s network access, but leave the shell out of it. idk if the last part is possible.