Disabling ssh-controlmaster mid --ssh session would tear down the
ControlMaster (if we own it) and silently redirect read/write/edit/bash
back to the local filesystem while the system prompt still claims we're
on the remote. Now blocked with an explanatory dialog.
Implementation: a DISABLE_GUARDS map keyed by bare extension name lets
specific extensions register a refusal predicate. ssh-controlmaster's
guard checks process.argv for --ssh and refuses if present. Easy to
extend with similar foot-guns later.
joakimp
c624eafe64