pub fn validate_control_frame(text: &str) -> Result<(), Error>Expand description
Refuses any outbound text frame the platform would not recognize as a control frame.
The platform’s failure mode for an unrecognized control frame is to type it into the
shell (sharp edge 1, measured: {"type":"window_size",...} became literal keystrokes
and a corrupted prompt). So the rule here is a strict allowlist of what the platform
is measured to accept — exactly {"type":"resize","cols":<n>,"rows":<n>} — and
anything else is refused client-side, where the failure is a sentence rather than
garbage in someone’s terminal.