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>

tests/AcDream.App.Tests/UI/ItemInteractionControllerTests.cs

@@ -31,6 +31,7 @@ public sealed class ItemInteractionControllerTests
         public readonly List<CombatMode> CombatModeRequests = new();
         public readonly CombatState Combat = new();
         public readonly StackSplitQuantityState SplitQuantity = new();
+        public readonly InventoryTransactionState? SharedTransactions;
         public uint SelectedObject;
         public bool NonCombatMode;
         public bool DragOnPlayerOpensSecureTrade = true;
@@ -38,7 +39,8 @@ public sealed class ItemInteractionControllerTests
         public long Now = 1_000;
 
         public Harness(
-            Action<uint, ItemUseRequestReservation>? requestUse = null)
+            Action<uint, ItemUseRequestReservation>? requestUse = null,
+            bool sharedTransactions = false)
         {
             Objects.AddOrUpdate(new ClientObject
             {
@@ -54,6 +56,9 @@ public sealed class ItemInteractionControllerTests
                 ItemsCapacity = 24,
             });
             Objects.MoveItem(Pack, Player, 0);
+            SharedTransactions = sharedTransactions
+                ? new InventoryTransactionState(Objects)
+                : null;
 
             Controller = new ItemInteractionController(
                 Objects,
@@ -86,7 +91,8 @@ public sealed class ItemInteractionControllerTests
                 },
                 combatState: Combat,
                 sendChangeCombatMode: CombatModeRequests.Add,
-                requestUse: requestUse);
+                requestUse: requestUse,
+                transactions: SharedTransactions);
         }
 
         public ItemInteractionController Controller { get; }
@@ -312,6 +318,39 @@ public sealed class ItemInteractionControllerTests
         Assert.False(h.Controller.IsAnyTargetModeActive);
     }
 
+    [Fact]
+    public void BorrowedTransactionOwnerIsExactAndOutlivesController()
+    {
+        var h = new Harness(sharedTransactions: true);
+
+        h.Controller.IncrementBusyCount();
+
+        Assert.Equal(1, h.SharedTransactions!.BusyCount);
+        h.Controller.Dispose();
+        Assert.False(h.SharedTransactions.IsDisposed);
+
+        h.SharedTransactions.ClearBusy();
+        Assert.Equal(0, h.SharedTransactions.BusyCount);
+        h.SharedTransactions.Dispose();
+    }
+
+    [Fact]
+    public void BorrowedTransactionOwnerRejectsDifferentObjectTable()
+    {
+        var objects = new ClientObjectTable();
+        using var transactions =
+            new InventoryTransactionState(new ClientObjectTable());
+
+        Assert.Throws<ArgumentException>(() => new ItemInteractionController(
+            objects,
+            playerGuid: () => Player,
+            sendUse: null,
+            sendUseWithTarget: null,
+            sendWield: null,
+            sendDrop: null,
+            transactions: transactions));
+    }
+
     [Fact]
     public void AppraisalResponse_releasesOneBusyReferenceAndAcceptsCurrentRefresh()
     {
@@ -2019,6 +2058,67 @@ public sealed class ItemInteractionControllerTests
         Assert.False(h.Controller.TryGetPendingInventoryRequest(out _));
     }
 
+    [Fact]
+    public void ThrowingReservedDispatchWithdrawsBothOwnersBeforeRethrow()
+    {
+        var h = new Harness();
+        const uint item = 0x70000A27u;
+        h.Objects.AddOrUpdate(new ClientObject
+        {
+            ObjectId = item,
+            Name = "Loot",
+            Type = ItemType.Misc,
+        });
+        var cancelled = new List<PendingBackpackPlacement>();
+        h.Controller.PendingBackpackPlacementCancelled += cancelled.Add;
+
+        Assert.Throws<InvalidOperationException>(() =>
+            h.Controller.TryDispatchPendingBackpackPlacement(
+                item,
+                Player,
+                0,
+                InventoryRequestKind.Pickup,
+                static () => throw new InvalidOperationException("transport")));
+
+        Assert.False(h.Controller.TryGetPendingBackpackPlacement(item, out _));
+        Assert.False(h.Controller.TryGetPendingInventoryRequest(out _));
+        Assert.Single(cancelled);
+    }
+
+    [Fact]
+    public void ThrowingPendingProjectionObserverRollsBackEveryOwner()
+    {
+        var h = new Harness();
+        const uint item = 0x70000A28u;
+        h.Objects.AddOrUpdate(new ClientObject
+        {
+            ObjectId = item,
+            Name = "Loot",
+            Type = ItemType.Misc,
+        });
+        bool firstObserved = false;
+        bool cancelled = false;
+        h.Controller.PendingBackpackPlacementRequested += _ =>
+            firstObserved = true;
+        h.Controller.PendingBackpackPlacementRequested += _ =>
+            throw new InvalidOperationException("projection");
+        h.Controller.PendingBackpackPlacementCancelled += _ =>
+            cancelled = true;
+
+        Assert.Throws<AggregateException>(() =>
+            h.Controller.TryDispatchPendingBackpackPlacement(
+                item,
+                Player,
+                0,
+                InventoryRequestKind.Pickup,
+                static () => true));
+
+        Assert.True(firstObserved);
+        Assert.True(cancelled);
+        Assert.False(h.Controller.TryGetPendingBackpackPlacement(item, out _));
+        Assert.False(h.Controller.TryGetPendingInventoryRequest(out _));
+    }
+
     [Fact]
     public void ResetSession_ClearsTargetBusyThrottleAndConsumedClickState()
     {