feat(ui): centralize retail selection state

src/AcDream.App/Studio/FixtureProvider.cs

@@ -113,6 +113,7 @@ public static class FixtureProvider
                 uint mainPackEmpty  = ItemListCellTemplate.ResolveEmptySprite(dats, 0x21000022u, 0x100001C9u);
 
                 var iconIds = MakeIconIds(stack);
+                var selection = new AcDream.Core.Selection.SelectionState();
 
                 InventoryController.Bind(
                     layout,
@@ -120,6 +121,7 @@ public static class FixtureProvider
                     playerGuid:             () => SampleData.PlayerGuid,
                     iconIds:                iconIds,
                     strength:               () => 100,
+                    selection:              selection,
                     datFont:                stack.VitalsDatFont,
                     contentsEmptySprite:    contentsEmpty,
                     sideBagEmptySprite:     sideBagEmpty,
@@ -133,6 +135,7 @@ public static class FixtureProvider
                     objects,
                     playerGuid:       () => SampleData.PlayerGuid,
                     iconIds:          iconIds,
+                    selection:        selection,
                     sendWield:        null,       // no live session in the studio
                     emptySlotSprite:  contentsEmpty,
                     datFont:          stack.VitalsDatFont);