225c20daeb
Solo pollers park (3001 RETRY); two concurrent pollers pair and both receive 3004 + same BattleId. Cache hits on the first arriver's next poll. ?scripted=1 retains today's solo Scripted path for dev work. Response DTO's BattleId/NodeServerUrl become nullable so 3001 omits them on the wire (WhenWritingNull policy drops them). ASP.NET's default bool binder rejects "1" as a value, so the scripted opt-in is bound as string? and parsed permissively (accepts "1" and "true"/"True"/etc.) rather than relying on built-in bool binding.