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(