Function resolve 

pub fn resolve(
    target: &Utf8Path,
    forge_flag: Option<&str>,
    repo_flag: Option<&str>,
) -> Result<Resolved, RkError>

Resolve the forge and the repository a forge verb acts on, in one pass: the flags override, and the origin remote answers otherwise.

An unrecognized host refuses rather than defaulting: a forge call against the wrong API is a half-run setup that looks done.

Errors

Returns RkError::Usage for an unknown --forge value, and a refusal naming the override when no forge resolves.