Replace all Task.Delay-based interest propagation waits with active probe loops
(PeriodicTimer + publish-and-read) in GatewayFailoverTests, LeafNodeFailoverTests,
JetStreamClusterTests, and RaftConsensusTests. Fix SW003 empty-catch violations in
ClusterResilienceTests by adding _ = e discard statements. Correct State.Messages
type from ulong to long to match the NATS.Client.JetStream API.
