Function settle_effect 

pub fn settle_effect(
    lease: &ClaimLease,
    progress: EffectProgress,
    recorded_output_digest: Option<&str>,
    completion: &EffectCompletion,
) -> CompletionVerdict

Decide one reported completion against the exact claim that owns it.

Duplicate completions and late owner results therefore cannot duplicate effects or release invalid successors: only the first matching completion is CompletionVerdict::Accepted, and every other report is inert.