* docs(computer): clarify screenshot output requirements
* fix(cli): do not advertise an unshipped --probe flag
The capabilities help line referenced --probe, which does not exist yet;
it ships in a later change. Advertising it here would be false until then.
* fix(cli): align computer-use screenshot guidance
* docs(computer): document inline screenshot fallback
* docs(computer): keep screenshot summary accurate
* docs(computer): keep screenshot guidance general