refactor(runtime): own inventory transaction state

Move the retail one-request-at-a-time gate, shared use busy references, external-container state, item mana, shortcuts, and desired-component snapshots into one Runtime-owned graph over J3's exact ClientObjectTable. Retained UI and session routing now borrow that owner; reset and shutdown preserve the existing order while failure/reentrancy tests protect the transaction boundary.

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

src/AcDream.App/Rendering/GameWindowLifetime.cs

@@ -84,6 +84,7 @@ internal sealed record LiveShutdownRoots(
     EquippedChildRenderController? EquippedChildren,
     LiveEntityRuntime? LiveEntities,
     RuntimeEntityObjectLifetime EntityObjects,
+    RuntimeInventoryState Inventory,
     RuntimeCommunicationState Communication,
     RenderSceneShadowRuntime? RenderSceneShadow,
     LivePresentationRuntimeBindings? PresentationBindings,
@@ -390,6 +391,9 @@ internal static class GameWindowShutdownManifest
             ]),
             new ResourceShutdownStage("runtime entity/object stream",
             [
+                Hard(
+                    "runtime inventory state",
+                    live.Inventory.Dispose),
                 Hard(
                     "runtime entity/object lifetime",
                     live.EntityObjects.Dispose),