feat(worker): event sink records OnWriteComplete rows into the completion cache

src/ZB.MOM.WW.MxGateway.Worker.Tests/MxAccess/MxAccessBaseEventSinkTests.cs

@@ -110,6 +110,47 @@ public sealed class MxAccessBaseEventSinkTests
         Assert.Same(cache, sink.ValueCache);
     }
 
+    /// <summary>
+    /// Verifies that an OnWriteComplete COM callback records the completion into
+    /// the per-session write-completion cache for the executor's bounded reply
+    /// wait AND still enqueues the event unchanged for the outbound stream —
+    /// correlation observes the event, it never consumes it. The cache update
+    /// fires only after the event has cleared the queue (post-publish rule).
+    /// </summary>
+    [Fact]
+    public void OnWriteComplete_ComCallback_RecordsCompletionAndStillEnqueuesEvent()
+    {
+        MxAccessEventQueue queue = new();
+        MxAccessWriteCompletionCache completionCache = new();
+        MxAccessBaseEventSink sink = new(queue, new MxAccessEventMapper(), new MxAccessValueCache(), completionCache);
+        MXSTATUS_PROXY[] statuses = Array.Empty<MXSTATUS_PROXY>();
+
+        sink.OnWriteComplete(hLMXServerHandle: 7, phItemHandle: 21, ref statuses);
+
+        Assert.Equal(1, queue.Count);
+        Assert.True(queue.TryDequeue(out WorkerEvent? workerEvent));
+        MxEvent mxEvent = workerEvent!.Event;
+        Assert.Equal(MxEventFamily.OnWriteComplete, mxEvent.Family);
+        Assert.Equal(7, mxEvent.ServerHandle);
+        Assert.Equal(21, mxEvent.ItemHandle);
+        Assert.Equal(1UL, completionCache.CurrentVersion(7, 21));
+    }
+
+    /// <summary>
+    /// Verifies that the sink-bound write-completion cache is exposed for sharing
+    /// with the owning <see cref="MxAccessSession"/> so the sink's recordings and
+    /// the write executor's waits see the same instance.
+    /// </summary>
+    [Fact]
+    public void WriteCompletionCache_ReturnsTheInstanceBoundAtConstruction()
+    {
+        MxAccessEventQueue queue = new();
+        MxAccessWriteCompletionCache completionCache = new();
+        MxAccessBaseEventSink sink = new(queue, new MxAccessEventMapper(), new MxAccessValueCache(), completionCache);
+
+        Assert.Same(completionCache, sink.WriteCompletionCache);
+    }
+
     /// <summary>
     /// Verifies that consecutive OnDataChange callbacks land in the queue with monotonic sequences.
     /// </summary>