fix(ui): assess retained items on right click

Port UIElement_ItemList's physical-item right-click branch through the shared retained list. Select and appraise backpack, loot, paperdoll, and shortcut items through their canonical owners, while preventing RMB movement from lifting items or issuing appraisal requests.

Co-authored-by: Codex <codex@openai.com>

src/AcDream.App/UI/UiItemSlot.cs

@@ -274,6 +274,11 @@ public class UiItemSlot : UiElement
             case UiEventType.DoubleClick:
                 DoubleClicked?.Invoke();
                 return true;
+            case UiEventType.RightClick:
+                if (ItemId != 0
+                    && FindList() is { ExamineItemRequested: { } examine })
+                    examine(ItemId);
+                return true;
 
             case UiEventType.DragBegin:
                 // Notify the source list's handler so it can lift (remove + wire) — retail