ZK Proof Gates Atomic x402 Agent Payments, Slashing Settlement Costs 84%

x402 enables agent payments but lacks execution-correctness guarantees. ZkInferenceEscrow reference design closes this gap: payment settles atomically only when on-chain ZK proof verifies pinned-circuit execution. Base Sepolia deployment: ~970k gas solo, ~84% reduction with channel funding and batched verification. Escrow-opening dominates costs, not verification. Facilitator becomes optional.