attempt 1 → HTTP 200 {"id":"0d64cb86-c769-43ae-a874-a2c44ad0451e","contextId":"c3b2050d-9270-4e1e-9721-a1b3798a1868","status":{"state":"TASK_STATE_COMPLETED","timestamp":"2026-10-23
attempt 2 → HTTP 200 {"id":"1a652e2a-421d-4244-b2c0-6965c1f2799b","contextId":"28790030-505a-4e91-9a84-4dc754ddff20","status":{"state":"TASK_STATE_COMPLETED","timestamp":"2026-10-23
attempt 2 reuses the SAME nonce+signature — expect 401/4xx, never 2xx