Function merged_request_for 

pub fn merged_request_for(
    cli: &Path,
    target: &Path,
    forge: Forge,
    repo: &str,
    tip: &str,
) -> Class

Ask the forge for the requests carrying one commit and judge the answer.

Every failure keeps the branch: a spawn error or an unclassifiable exit is Unknown, and a 404 — a tip the forge never saw — is Unconfirmed.