fix(grpc): typed alarm-feed overflow, memoized alarm snapshot, cancellable stream writes, uniform reply correlation id

- StreamAlarms: slow subscribers are completed with
  AlarmFeedSubscriberOverflowException and surface as ResourceExhausted
  (like a StreamEvents overflow) instead of warning-with-stack + Unavailable.
- GatewayAlarmMonitor.StreamAsync reuses the memoized alarm-set projection
  instead of cloning the whole set under the broadcast lock per attach; the
  prefix filter runs outside the lock.
- StreamEvents/StreamAlarms pass the call token to response writes; a write
  failure after client cancel maps to Cancelled without a warning.
- Every MxCommandReply.correlation_id now echoes the request's
  client_correlation_id (previously only constraint-denied replies did;
  normal replies leaked the internal envelope id).

src/ZB.MOM.WW.MxGateway.Tests/TestSupport/FakeGatewayAlarmService.cs

@@ -40,8 +40,18 @@ public sealed class FakeGatewayAlarmService : IGatewayAlarmService
 
         yield return new AlarmFeedMessage { SnapshotComplete = true };
         await Task.CompletedTask.ConfigureAwait(false);
+        if (StreamFault is not null)
+        {
+            throw StreamFault;
+        }
     }
 
+    /// <summary>
+    ///     Gets or sets an exception the feed throws after its snapshot, standing in for the monitor
+    ///     completing a subscriber with a fault (for example a slow-subscriber overflow).
+    /// </summary>
+    public Exception? StreamFault { get; set; }
+
     /// <inheritdoc />
     public Task<AcknowledgeAlarmReply> AcknowledgeAsync(
         AcknowledgeAlarmRequest request,