fix: NPC outfits no longer stack two items on one layer (#2715)

Companion to #2712, which covers HireRanger's refused `EquipItem`. A sweep that built every constructible Mobile 2,000 times under each expansion found these other outfits that put two items on one layer. They don't leak, because `AddItem` skips `CheckEquip`, but the NPC wears both items and the client draws only one.

| NPC | Conflict |
|---|---|
| Miner, Ranger, Thief | Own shirt/pants/ThighBoots added on top of the random `BaseVendor.InitOutfit` (shoes doubled on every spawn) |
| MasterTheophilus | Shoes + Robe added over `EvilMageLord`'s Sandals + Robe |
| Merchant | Shirt + FancyShirt, or PlainDress + FancyDress |
| IronWorker | Bandana/JesterHat + Bascinet |
| MeerCaptain | One-handed sword + Crossbow |
| BakeKitsune | `BodyMod` isn't saved, so after a restart `RemoveDisguise` bailed and the next `Disguise()` stacked a second robe and pair of shoes |

## Changes
- `BaseCreature.ReplaceEquipment(item)` equips an item in place of whatever an inherited outfit put on its layer, and deletes the item if it still can't be equipped.
- Miner, Ranger, Thief, MasterTheophilus: their own pieces replace the inherited ones.
- Merchant and IronWorker: dropped the duplicate roll. Each kept the item the client was already drawing, which is the last one sent: the fancy set and the Bascinet.
- MeerCaptain: the sword goes into its pack as loot. **Behavior change:** `Mobile.Weapon` checks the one-handed layer first, so it was fighting with the sword despite its archer AI, its Archery skill and the bolts in its pack. It now uses the crossbow.
- BakeKitsune: `RemoveDisguise` strips the disguise without checking `IsBodyMod`.

## Testing
- I re-ran the sweep (local diagnostic, not committed; needs client tiledata) at 500 rolls × 12 expansions. Only HireRanger (#2712) and LordOaks (separate fix coming) remain.
- UOContent.Tests: 1218 passed, 2 skipped.

Projects/UOContent/Mobiles/BaseCreature.cs

@@ -5724,6 +5724,20 @@ namespace Server.Mobiles
             }
         }
 
+        /// <summary>
+        ///     Equips <paramref name="item" /> in place of whatever an inherited outfit put on its layer.
+        ///     AddItem would stack both on one layer, and EquipItem would refuse and orphan the item.
+        /// </summary>
+        public void ReplaceEquipment(Item item)
+        {
+            FindItemOnLayer(item.Layer)?.Delete();
+
+            if (!EquipItem(item))
+            {
+                item.Delete();
+            }
+        }
+
         public virtual void HealStart(Mobile patient)
         {
             StopHeal();

Projects/UOContent/Mobiles/Monsters/LBR/Meers/MeerCaptain.cs

@@ -47,7 +47,8 @@ namespace Server.Mobiles
             pack.DropItem(new Bolt(Utility.RandomMinMax(10, 20)));
             pack.DropItem(new Bolt(Utility.RandomMinMax(10, 20)));
 
-            AddItem(
+            // The crossbow is wielded; the sword would share its hands, so it is carried as loot.
+            pack.DropItem(
                 Utility.Random(6) switch
                 {
                     0 => new Longsword(),

Projects/UOContent/Mobiles/Monsters/ML/Bedlam/MasterTheophilus.cs

@@ -42,8 +42,8 @@ namespace Server.Mobiles
             Fame = 18000;
             Karma = -18000;
 
-            AddItem(new Shoes(0x537));
-            AddItem(new Robe(0x452));
+            ReplaceEquipment(new Shoes(0x537));
+            ReplaceEquipment(new Robe(0x452));
 
             for (var i = 0; i < 2; ++i)
             {

Projects/UOContent/Mobiles/Monsters/SE/BakeKitsune.cs

@@ -176,11 +176,8 @@ namespace Server.Mobiles
         {
             _disguiseTimerToken.Cancel();
 
-            if (!IsBodyMod)
-            {
-                return;
-            }
-
+            // BodyMod is not saved, so after a restart a disguised kitsune comes back without it but still
+            // wearing the disguise; strip it regardless.
             Name = null;
             Title = null;
             BodyMod = 0;

Projects/UOContent/Mobiles/Townfolk/Merchant.cs

@@ -33,15 +33,6 @@ public partial class Merchant : BaseEscortable
 
     public override void InitOutfit()
     {
-        if (Female)
-        {
-            AddItem(new PlainDress());
-        }
-        else
-        {
-            AddItem(new Shirt(GetRandomHue()));
-        }
-
         var lowHue = GetRandomHue();
 
         AddItem(new ThighBoots());

Projects/UOContent/Mobiles/Vendors/NPC/IronWorker.cs

@@ -58,14 +58,6 @@ namespace Server.Mobiles
                 AddItem(new FullApron(Utility.RandomBrightHue()));
             }
 
-            AddItem(
-                Utility.Random(3) switch
-                {
-                    0 => new Bandana(Utility.RandomBrightHue()),
-                    _ => new JesterHat(Utility.RandomBrightHue()) // 1-2
-                }
-            );
-
             AddItem(new Bascinet());
             AddItem(new SmithHammer());
 

Projects/UOContent/Mobiles/Vendors/NPC/Miner.cs

@@ -26,10 +26,10 @@ namespace Server.Mobiles
         {
             base.InitOutfit();
 
-            AddItem(new FancyShirt(0x3E4));
-            AddItem(new LongPants(0x192));
+            ReplaceEquipment(new FancyShirt(0x3E4));
+            ReplaceEquipment(new LongPants(0x192));
             AddItem(new Pickaxe());
-            AddItem(new ThighBoots(0x283));
+            ReplaceEquipment(new ThighBoots(0x283));
         }
     }
 }

Projects/UOContent/Mobiles/Vendors/NPC/Ranger.cs

@@ -31,10 +31,10 @@ namespace Server.Mobiles
         {
             base.InitOutfit();
 
-            AddItem(new Shirt(Utility.RandomNeutralHue()));
-            AddItem(new LongPants(Utility.RandomNeutralHue()));
+            ReplaceEquipment(new Shirt(Utility.RandomNeutralHue()));
+            ReplaceEquipment(new LongPants(Utility.RandomNeutralHue()));
             AddItem(new Bow());
-            AddItem(new ThighBoots(Utility.RandomNeutralHue()));
+            ReplaceEquipment(new ThighBoots(Utility.RandomNeutralHue()));
         }
     }
 }

Projects/UOContent/Mobiles/Vendors/NPC/Thief.cs

@@ -31,10 +31,10 @@ namespace Server.Mobiles
         {
             base.InitOutfit();
 
-            AddItem(new Shirt(Utility.RandomNeutralHue()));
-            AddItem(new LongPants(Utility.RandomNeutralHue()));
+            ReplaceEquipment(new Shirt(Utility.RandomNeutralHue()));
+            ReplaceEquipment(new LongPants(Utility.RandomNeutralHue()));
             AddItem(new Dagger());
-            AddItem(new ThighBoots(Utility.RandomNeutralHue()));
+            ReplaceEquipment(new ThighBoots(Utility.RandomNeutralHue()));
         }
     }
 }