Function load_session_with_fidelity 

pub fn load_session_with_fidelity(
    locator: &SessionLocator,
    fidelity: Fidelity,
) -> Result<Session>

load_session at a declared fidelity.

Read-only surfaces pass Fidelity::Semantic so a transcript whose record graph cannot be reconstructed exactly still renders, with the degradation named in Session::load_residue. Continuation, transfer and export callers keep the strict default of load_session.