Function resolve_session_arg 

pub fn resolve_session_arg(
    store: &SessionStore,
    query: &str,
) -> Result<(PathBuf, Session)>

Resolve the user’s <session> argument (which may be a substring) to a concrete session. CLI policy, not store policy: substring matching is an ergonomic affordance for the user typing outrig logs 1419 fs, but the store’s contract stays “exact id or path.”

Tries an exact get_by_id first (so the common case is one stat). On miss, falls back to a list() substring match. Zero matches -> not-found error; multiple -> OutrigError::Configuration with the candidate ids one per line.