fix(items): complete retail corpse looting feedback

Route corpse Use through the shared ItemHolder policy so Stuck corpses open instead of being sent as pickup requests. Restore the framed, horizontally resizable external-container strip and use a compact initial width. Port retail's target-list pending item projection so loot is marked in the chosen inventory slot without changing canonical ownership before the server confirms.

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

src/AcDream.App/UI/Layout/ExternalContainerController.cs

@@ -21,6 +21,10 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
 
     private const float ItemCellSize = 32f;
     private const float ContainerCellSize = 36f;
+    // User-directed retained default: the raw 800-pixel LayoutDesc remains
+    // horizontally reachable by resize/persistence but opens less wide.
+    internal const float DefaultContentWidth = 700f;
+    internal const float MinimumContentWidth = 160f;
 
     private readonly ExternalContainerState _state;
     private readonly ClientObjectTable _objects;
@@ -144,6 +148,32 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
             contentsEmptySprite,
             containerEmptySprite);
 
+    /// <summary>
+    /// Retail's root authors only the tiled center surface; the common floating-window
+    /// bevel surrounds it. Its Left/Right edge rules stretch every horizontal list and
+    /// pin the close button, so this strip resizes on X only.
+    /// </summary>
+    internal static RetailWindowFrame.Options CreateWindowOptions(UiElement root)
+        => new()
+        {
+            WindowName = WindowNames.ExternalContainer,
+            Chrome = RetailWindowChrome.NineSlice,
+            Left = root.Left,
+            Top = root.Top,
+            ContentWidth = Math.Min(root.Width, DefaultContentWidth),
+            ContentHeight = root.Height,
+            MinWidth = MinimumContentWidth + 2f * RetailChromeSprites.Border,
+            Visible = false,
+            Draggable = true,
+            Resizable = true,
+            ResizeX = true,
+            ResizeY = false,
+            ResizableEdges = ResizeEdges.Left | ResizeEdges.Right,
+            ConstrainDragToParent = true,
+            ConstrainResizeToParent = true,
+            DrawChromeCenter = false,
+        };
+
     public void Tick()
     {
         uint root = _state.CurrentContainerId;