Function check_admissibility 

pub fn check_admissibility(
    proposal: &EffectProposal,
    capabilities: &[Capability],
    state: &KernelState,
) -> AdmissibilityWitness

Evaluate the admissibility predicate Adm(x, p, x') for a proposal against the actor’s capabilities and current kernel state.

Returns an AdmissibilityWitness recording each clause and the decision. Every effect SHALL be mediated by such a witness before any durable effect occurs (PSP-8 Gate E).