fix: complete retail parity stability pass

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

@@ -2290,6 +2290,7 @@ public sealed class LiveEntityHydrationControllerTests
         Assert.True(fixture.Runtime.TryGetRecord(splitResultGuid, out LiveEntityRecord record));
         Assert.NotNull(record.WorldEntity);
         Assert.Equal(1, fixture.Resources.RegisterCount);
+        Assert.Equal(splitResultGuid, drop.Selection.SelectedObjectId);
     }
 
     [Fact]
@@ -2372,6 +2373,7 @@ public sealed class LiveEntityHydrationControllerTests
         Assert.False(secondRecovered);
         Assert.False(fixture.Runtime.TryGetSnapshot(secondUnknown, out _));
         Assert.True(fixture.Runtime.TryGetSnapshot(firstUnknown, out _));
+        Assert.Equal(firstUnknown, drop.Selection.SelectedObjectId);
         Assert.Equal(1, fixture.Resources.RegisterCount);
     }
 
@@ -2476,7 +2478,7 @@ public sealed class LiveEntityHydrationControllerTests
         public readonly ItemInteractionController Interaction;
         public readonly InventoryWorldDropProjectionController Projection;
         public readonly StackSplitQuantityState SplitQuantity = new();
-        public uint SelectedObject;
+        public readonly AcDream.Core.Selection.SelectionState Selection = new();
 
         public DropHarness(Fixture fixture)
         {
@@ -2498,7 +2500,7 @@ public sealed class LiveEntityHydrationControllerTests
                 sendWield: null,
                 sendDrop: _ => { },
                 sendSplitToWorld: (_, _) => { },
-                selectedObjectId: () => SelectedObject,
+                selectedObjectId: () => Selection.SelectedObjectId ?? 0u,
                 stackSplitQuantity: SplitQuantity,
                 playerOnGround: () => true);
             Projection = new InventoryWorldDropProjectionController(
@@ -2506,12 +2508,15 @@ public sealed class LiveEntityHydrationControllerTests
                 fixture.Objects,
                 fixture.Runtime,
                 fixture.Controller,
+                Selection,
                 () => 100.0);
         }
 
         public bool DispatchSplit(uint itemGuid, uint stackSize, uint splitAmount)
         {
-            SelectedObject = itemGuid;
+            Selection.Select(
+                itemGuid,
+                AcDream.Core.Selection.SelectionChangeSource.Inventory);
             SplitQuantity.Reset(stackSize);
             SplitQuantity.SetValue(splitAmount);
             var payload = new ItemDragPayload(

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

@@ -28,12 +28,13 @@ internal static class LiveEntityTestFixture
         WorldSession.EntitySpawn spawn,
         Func<uint, WorldEntity>? factory = null,
         LiveEntityProjectionKind projectionKind = LiveEntityProjectionKind.World,
-        Action<LiveEntityRecord>? initializeProjection = null)
+        Action<LiveEntityRecord>? initializeProjection = null,
+        bool isLocalPlayer = false)
     {
         ArgumentNullException.ThrowIfNull(runtime);
 
         LiveEntityRegistrationResult registration =
-            runtime.RegisterLiveEntity(spawn);
+            runtime.RegisterLiveEntity(spawn, isLocalPlayer);
         RuntimeEntityRecord canonical = registration.Canonical
             ?? throw new InvalidOperationException(
                 "The fixture cannot materialize a stale CreateObject.");

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()
     {