Deterministic procedure for an agent that must pay for a long-running or asynchronous job over x402/MPP (video generatio

Deterministic procedure for an agent that must pay for a long-running or asynchronous job over x402/MPP (video generation, scraping, inference, batch processing). Covers: submit-payment split (pay only for submission, never for the whole job up front), polling budget with max polls and max total spend across polls, cancel-before-completion refund thresholds, resume-after-timeout rules with re-payment guardrails, job-status code interpretation (queued/running/succeeded/failed/canceled), and a