Add a shell-execution mode that never touches the model or context

Since v2.1.186, !<command> at the prompt injects the command's output into context and triggers an automatic API call so Claude responds to it. Setting "respondToBashCommands": false in settings.json restores the pre-2.1.186 behavior: output still goes into context, but Claude doesn't auto-respond.

Neither option gives you a way to run a shell command that stays entirely local. If I run ls, git status, or some other one-off check between turns, I don't want it in context and I definitely don't want it triggering a response. Right now every ! command costs either a full turn or at least some context, with no way around it.

Request: a separate syntax, something like !!<command>, that runs the command in the shell and prints output to the terminal only. No context injection, no API call.

Version: 2.1.201 (macOS)