.NET client: port stream-alarms and acknowledge-alarm + fix stream-events OCE

Adds the session-less alarm CLI subcommands. stream-alarms attaches to the
gateway's central alarm feed (--filter-prefix, --max-events, --json/--jsonl);
acknowledge-alarm is a unary ack (--reference required, --comment, --operator).
StreamAlarmsAsync joins QueryActiveAlarmsAsync on MxGatewayClient and the
transport interface; the CLI client interface, adapter, and FakeGatewayTransport
follow.

Also fixes the OCE bug exposed by -VerifyWrite in the cross-language e2e:
StreamEventsAsync's await foreach now swallows OperationCanceledException when
the supplied cancellation token is the one that fired (graceful end-of-window),
and RunBatchAsync no longer excludes OCE from its outer catch — so a streaming
command that hits its --timeout reports a JSON error inside its EOR-delimited
record instead of killing the long-lived batch process.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

clients/dotnet/ZB.MOM.WW.MxGateway.Client/GrpcMxGatewayClientTransport.cs

@@ -175,6 +175,48 @@ internal sealed class GrpcMxGatewayClientTransport(
         return QueryActiveAlarmsAsync(request, callOptions);
     }
 
+    /// <inheritdoc />
+    public async IAsyncEnumerable<AlarmFeedMessage> StreamAlarmsAsync(
+        StreamAlarmsRequest request,
+        CallOptions callOptions,
+        [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        CancellationToken effectiveCancellationToken = cancellationToken.CanBeCanceled
+            ? cancellationToken
+            : callOptions.CancellationToken;
+
+        using AsyncServerStreamingCall<AlarmFeedMessage> call = RawClient.StreamAlarms(request, callOptions);
+
+        IAsyncStreamReader<AlarmFeedMessage> responseStream = call.ResponseStream;
+        while (true)
+        {
+            AlarmFeedMessage? message;
+            try
+            {
+                if (!await responseStream.MoveNext(effectiveCancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+
+                message = responseStream.Current;
+            }
+            catch (RpcException exception)
+            {
+                throw MapRpcException(exception, effectiveCancellationToken);
+            }
+
+            yield return message;
+        }
+    }
+
+    /// <inheritdoc />
+    IAsyncEnumerable<AlarmFeedMessage> IMxGatewayClientTransport.StreamAlarmsAsync(
+        StreamAlarmsRequest request,
+        CallOptions callOptions)
+    {
+        return StreamAlarmsAsync(request, callOptions);
+    }
+
     private static Exception MapRpcException(
         RpcException exception,
         CancellationToken cancellationToken)

clients/dotnet/ZB.MOM.WW.MxGateway.Client/IMxGatewayClientTransport.cs

@@ -75,4 +75,15 @@ internal interface IMxGatewayClientTransport
     IAsyncEnumerable<ActiveAlarmSnapshot> QueryActiveAlarmsAsync(
         QueryActiveAlarmsRequest request,
         CallOptions callOptions);
+
+    /// <summary>
+    /// Attaches to the gateway's central alarm feed — the current active-alarm
+    /// snapshot followed by live transitions.
+    /// </summary>
+    /// <param name="request">The stream request, optionally scoped by alarm-reference prefix.</param>
+    /// <param name="callOptions">gRPC call options.</param>
+    /// <returns>An async enumerable of alarm feed messages.</returns>
+    IAsyncEnumerable<AlarmFeedMessage> StreamAlarmsAsync(
+        StreamAlarmsRequest request,
+        CallOptions callOptions);
 }

clients/dotnet/ZB.MOM.WW.MxGateway.Client/MxGatewayClient.cs

@@ -224,6 +224,28 @@ public sealed class MxGatewayClient : IAsyncDisposable
         return _transport.QueryActiveAlarmsAsync(request, CreateStreamCallOptions(cancellationToken));
     }
 
+    /// <summary>
+    /// Attaches to the gateway's central alarm feed. The stream opens with one
+    /// <see cref="AlarmFeedMessage"/> per currently-active alarm (the
+    /// ConditionRefresh snapshot), then a single <c>snapshot_complete</c>, then a
+    /// <c>transition</c> for every subsequent raise / acknowledge / clear. Served
+    /// by the gateway's always-on alarm monitor — no worker session is opened, so
+    /// any number of clients may attach. Optionally scoped by alarm-reference
+    /// prefix (<see cref="StreamAlarmsRequest.AlarmFilterPrefix"/>).
+    /// </summary>
+    /// <param name="request">The stream request, optionally scoped by alarm-reference prefix.</param>
+    /// <param name="cancellationToken">Cancellation token for the stream.</param>
+    /// <returns>An async enumerable of alarm feed messages.</returns>
+    public IAsyncEnumerable<AlarmFeedMessage> StreamAlarmsAsync(
+        StreamAlarmsRequest request,
+        CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(request);
+        ThrowIfDisposed();
+
+        return _transport.StreamAlarmsAsync(request, CreateStreamCallOptions(cancellationToken));
+    }
+
     /// <summary>
     /// Disposes the client and releases all resources.
     /// </summary>