7f9ee493b6
Implements the background loop (Go: monitorCluster) that reads RaftLogEntry items from a channel and dispatches assignStream, removeStream, assignConsumer, removeConsumer, and snapshot operations to JetStreamMetaGroup. - Add five public mutation helpers to JetStreamMetaGroup (AddStreamAssignment, RemoveStreamAssignment, AddConsumerAssignment, RemoveConsumerAssignment, ReplaceAllAssignments) used by the monitor path - JetStreamClusterMonitor: async loop over ChannelReader<RaftLogEntry>, JSON dispatch, ILogger injection with NullLogger default, malformed entries logged and skipped rather than aborting the loop - WaitForProcessedAsync uses Monitor.PulseAll for race-free test synchronisation with no Task.Delay — satisfies slopwatch SW003/SW004 rules - 10 new targeted tests all pass; 1101 cluster regression tests unchanged