refactor(runtime): close canonical gameplay ownership

Unify the toolbar shortcut manager with Runtime inventory state, route retail-ordered shortcut and spellbook command effects through the canonical owners, and make retained controllers borrow those exact instances. Remove the item-interaction transaction fallback and add graphical/no-window parity plus failure-safe terminal ownership-ledger coverage.

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

src/AcDream.App/Studio/FixtureProvider.cs

@@ -117,7 +117,7 @@ public static class FixtureProvider
                 return ToolbarController.Bind(
                     layout,
                     objects,
-                    shortcuts:  () => System.Array.Empty<ShortcutEntry>(),
+                    shortcuts:  new ShortcutStore(),
                     iconIds:    MakeIconIds(stack),
                     useItem:    _ => { },
                     combatState: null,
@@ -141,6 +141,7 @@ public static class FixtureProvider
                 var selection = new AcDream.Core.Selection.SelectionState();
                 var itemInteraction = new ItemInteractionController(
                     objects,
+                    new InventoryTransactionState(objects),
                     () => SampleData.PlayerGuid,
                     sendUse: null,
                     sendUseWithTarget: null,