fix: complete retail parity stability pass

tests/AcDream.App.Tests/World/RuntimePlacementPresentationSinkTests.cs

@@ -356,6 +356,48 @@ public sealed class RuntimePlacementPresentationSinkTests
         Assert.Equal(priorVisible, record.IsSpatiallyVisible);
     }
 
+    [Fact]
+    public void ExecutorCompleted_PoseOnlySupersessionDoesNotSnapSidecarBack()
+    {
+        Fixture fixture = Fixture.Create();
+        LiveEntityRecord record = fixture.Materialize(Spawn(Guid, 1, SourceCell));
+        WorldEntity entity = record.WorldEntity!;
+        var body = new PhysicsBody
+        {
+            Position = entity.Position,
+            Orientation = entity.Rotation,
+        };
+        record.Canonical.SetPhysicsBody(body);
+        RuntimePlacementProjectionSnapshot stale = Placement(
+            fixture,
+            record,
+            RuntimePlacementProjectionKind.ExecutorCompleted,
+            body.Position,
+            body.Orientation);
+
+        // #323: StoreAcceptedDestinationPose has this exact shape — it moves
+        // the retained body without changing cell or PlacementCommitVersion.
+        // A delayed initial-create receipt must acknowledge without restoring
+        // the older pose to the graphical sidecar.
+        var currentPosition = body.Position + new Vector3(25f, 10f, 3f);
+        Quaternion currentOrientation = Quaternion.CreateFromAxisAngle(
+            Vector3.UnitZ,
+            0.75f);
+        body.Position = currentPosition;
+        body.Orientation = currentOrientation;
+        entity.SetPosition(currentPosition);
+        entity.Rotation = currentOrientation;
+
+        Assert.True(fixture.Sink.TryApply(in stale));
+
+        Assert.Equal(currentPosition, entity.Position);
+        Assert.Equal(currentOrientation, entity.Rotation);
+        Assert.Equal(stale.Token.ExactCellId, record.FullCellId);
+        Assert.Equal(
+            stale.Token.PlacementCommitVersion,
+            record.Canonical.PlacementCommitVersion);
+    }
+
     [Fact]
     public void Place_RejectsStaleCanonicalVersionsWithoutChangingSidecar()
     {