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>

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

@@ -134,6 +134,30 @@ public sealed class ItemInteractionControllerTests
         Assert.Equal(chest, h.GroundObject);
     }
 
+    [Fact]
+    public void CorpseUse_UsesStuckContainerInsteadOfTryingToPickItUp()
+    {
+        var h = new Harness();
+        const uint corpse = 0x70000002u;
+        h.Objects.AddOrUpdate(new ClientObject
+        {
+            ObjectId = corpse,
+            Type = ItemType.Container,
+            ItemsCapacity = 24,
+            Useability = ItemUseability.Remote,
+            PublicWeenieBitfield = (uint)(
+                PublicWeenieFlags.Openable
+                | PublicWeenieFlags.Stuck
+                | PublicWeenieFlags.Corpse),
+        });
+
+        Assert.True(h.Controller.UseSelectedOrEnterMode(corpse));
+
+        Assert.Equal(new uint[] { corpse }, h.Uses);
+        Assert.Equal(new uint[] { corpse }, h.ExternalRequests);
+        Assert.Empty(h.Puts);
+    }
+
     [Fact]
     public void DropOwnedItemOnOpenExternalContainer_SendsPutWithoutOptimisticMove()
     {