fix: worn gear lifted off a corpse stays loot when put back (#2701)

A corpse's worn-gear list was fixed at creation, and clients learn worn gear only from the 0x89 packet sent on first sight. A piece lifted and dropped back showed as loose loot to everyone watching, but came back "worn" after a relog. Lifting now takes the piece off the list, so every view agrees it is loot.

Programmatic moves (the duel gather-and-re-equip in `DuelContext`) don't go through `OnItemLifted` and still see the original list.

Projects/UOContent.Tests/Tests/Items/Misc/Corpses/CorpseLootTests.cs

@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using Server;
+using Server.Items;
+using Xunit;
+
+namespace UOContent.Tests;
+
+[Collection("Sequential UOContent Tests")]
+public class CorpseLootTests
+{
+    [Fact]
+    public void LiftedWornGear_PutBack_StaysLoot()
+    {
+        var owner = new Mobile((Serial)0x1);
+        owner.DefaultMobileInit();
+        owner.Body = 0x190;
+
+        // Weapons take their layer from tiledata, which CI doesn't load.
+        var sword = new VikingSword { Layer = Layer.OneHanded };
+        Assert.True(owner.EquipItem(sword));
+
+        var corpse = new Corpse(owner, new List<Item> { sword });
+        corpse.DropItem(sword);
+
+        try
+        {
+            Assert.Contains(sword, corpse.EquipItems);
+
+            corpse.OnItemLifted(owner, sword);
+            sword.Internalize();
+            corpse.DropItem(sword);
+
+            Assert.Same(corpse, sword.Parent);
+            Assert.DoesNotContain(sword, corpse.EquipItems);
+        }
+        finally
+        {
+            corpse.Delete();
+            owner.Delete();
+        }
+    }
+}

Projects/UOContent/Items/Misc/Corpses/Corpse.cs

@@ -812,6 +812,10 @@ public partial class Corpse : Container, ICarvable
         AddToLooters(from);
 
         _instancedItems?.Remove(item);
+
+        // Lifted gear is loot from then on. Clients only learn worn gear from 0x89 on first sight, so a
+        // piece put back would show worn after a relog but loose to everyone already watching.
+        RemoveFromEquipItems(item);
     }
 
     public override void GetContextMenuEntries(Mobile from, ref PooledRefList<ContextMenuEntry> list)