Starts a PAID asynchronous observation and reserves funds. Use only after the customer approved this quote and maximum charge. Requires API Key, geo:run grant, approved=true, max_charge_cents and a stable idempotency_key. On insufficient balance, read payment_handoff and pause for the customer to contact the administrator; no online payment or automatic credit is available. Retry the same request with the same key; never silently switch targets, increase the budget or create a recurring schedule.