Contract 11.2.3

An observed unfinished colosseum owes one budgeted river-log check after its canonical season's nominal end, even while the current-race endpoint is in 404 standby. The existing current-race 404 hold, rate budget, live reserve and bounded retries remain intact. The check does not mark anything closed: final closure and awards still require recorded API log facts. The newer-observed-race catch-up remains. Response shapes and JSON API 3.0.0 are unchanged.