UFP x Dynamic Causal Foam Axis C0 v0.1.0: Predictive Closure of Spectral Boundary Observers

UFP x Dynamic Causal Foam Axis C0 v0.1.0 is a prospective experimental contract for testing whether coarse observables in a Dynamic Causal Foam toy substrate can form genuinely predictive effective descriptions without retaining nearly the full microscopic state. The experiment keeps two research roles separate. Dynamic Causal Foam supplies the candidate state space, local transition rule, boundary variables, spectral observables, defect variables, and probe observables. The UFP-NB1 predictive-sufficiency framework supplies the projection-closure criterion, stable predictive refinement, initialization-history analysis, and separate compile/startup/steady cost accounting. C0 freezes a cumulative observer ladder, exact and approximate predictive-leakage measures, stable refinement Q_C0, minimum history initializer h*, cost ledgers, anti-rescue rules, witness preservation, held-out validation, and deterministic execution receipts. The first finite experiment is designed to test every feasible system size under an independently frozen resource stopping rule rather than privileging N=7 or any other historically used size. This contract does not modify or reinterpret UFP-NB1 v0.3.0 and does not establish DCF physics. A null result in which all useful observers refine back toward the microscopic state is explicitly admissible and scientifically meaningful.