fix: a deleted character's followers, and familiars that never unregistered (#2675)

## Summary

**Followers of a deleted character.** `PlayerMobile.OnDelete` deleted stabled pets and left every active follower pointing at the deleted mobile. Pets stayed controlled by nobody, and after a restart they loaded as owned pets with no owner. Now, when a character is deleted:
- bonded or dead pets and summons (controlled or not) are deleted;
- unbonded pets are released: they go wild and despawn on the abandoned-pet timer;
- escorts and hirelings are left alone, because they already notice a deleted master and walk off on their own.

**Familiars and animated dead that never unregistered.** `BaseCreature` unregistered them in `OnAfterDelete`, after `OnDelete` had already cleared the master. Both calls did nothing, so `SummonFamiliarSpell.Table` and the animated-dead registry kept deleted creatures until the caster's next cast. The unregisters now run in `OnDelete`, before the master is cleared.

## Test plan

- [x] `DeletedMasterTests` (6 cases, all failing on main): unbonded pet released; bonded and bonded-dead pets deleted; controlled and uncontrolled summons deleted; familiar unregistered on delete
- [x] UOContent.Tests (1184 passed, 2 skipped) and Server.Tests (907) green

Projects/UOContent.Tests/Tests/Mobiles/DeletedMasterTests.cs

@@ -0,0 +1,114 @@
+using System;
+using System.Collections.Generic;
+using Server;
+using Server.Mobiles;
+using Server.Spells.Necromancy;
+using Xunit;
+
+namespace UOContent.Tests.Mobiles;
+
+// A deleted master must not leave creatures pointing at it.
+[Collection("Sequential UOContent Tests")]
+public class DeletedMasterTests : IDisposable
+{
+    private readonly List<Mobile> _created = [];
+
+    public void Dispose()
+    {
+        for (var i = 0; i < _created.Count; i++)
+        {
+            _created[i].Delete();
+        }
+    }
+
+    private sealed class Stub : BaseCreature
+    {
+        public Stub() : base(AIType.AI_Melee) => Body = 0xC9;
+
+        public Stub(Serial serial) : base(serial)
+        {
+        }
+    }
+
+    private Stub NewCreature()
+    {
+        var bc = new Stub();
+        _created.Add(bc);
+        return bc;
+    }
+
+    private PlayerMobile NewPlayer()
+    {
+        var pm = new PlayerMobile(World.NewMobile);
+        pm.DefaultMobileInit();
+        World.AddEntity(pm);
+        _created.Add(pm);
+        return pm;
+    }
+
+    [Fact]
+    public void DeletingAPlayer_ReleasesAnUnbondedPet()
+    {
+        var owner = NewPlayer();
+        var pet = NewCreature();
+        pet.SetControlMaster(owner);
+
+        owner.Delete();
+
+        Assert.False(pet.Deleted);
+        Assert.False(pet.Controlled);
+        Assert.Null(pet.Master);
+        Assert.True(pet.PendingDeleteTimer?.Running);
+    }
+
+    [Theory]
+    [InlineData(false)] // bonded
+    [InlineData(true)]  // bonded and dead
+    public void DeletingAPlayer_DeletesABondedPet(bool dead)
+    {
+        var owner = NewPlayer();
+        var pet = NewCreature();
+        pet.SetControlMaster(owner);
+        pet.IsBonded = true;
+        pet.IsDeadPet = dead;
+
+        owner.Delete();
+
+        Assert.True(pet.Deleted);
+    }
+
+    [Theory]
+    [InlineData(false)] // energy vortex
+    [InlineData(true)]  // controlled summon
+    public void DeletingAPlayer_DeletesItsSummons(bool controlled)
+    {
+        var caster = NewPlayer();
+        var summon = NewCreature();
+
+        if (controlled)
+        {
+            summon.SetControlMaster(caster);
+        }
+
+        summon.Summoned = true;
+        summon.Master = caster;
+
+        caster.Delete();
+
+        Assert.True(summon.Deleted);
+    }
+
+    [Fact]
+    public void DeletingAFamiliar_UnregistersIt()
+    {
+        var caster = NewPlayer();
+        var familiar = NewCreature();
+        familiar.SetControlMaster(caster);
+        familiar.Summoned = true;
+        SummonFamiliarSpell.Table[caster] = familiar;
+
+        familiar.Delete();
+
+        Assert.False(SummonFamiliarSpell.Table.ContainsKey(caster));
+    }
+}

Projects/UOContent/Mobiles/BaseCreature.cs

@@ -2717,16 +2717,6 @@ namespace Server.Mobiles
 
             FocusMob = null;
 
-            if (IsAnimatedDead)
-            {
-                AnimateDeadSpell.Unregister(SummonMaster, this);
-            }
-
-            if (SummonMaster != null)
-            {
-                SummonFamiliarSpell.Unregister(SummonMaster, this);
-            }
-
             if (MLQuestSystem.Enabled)
             {
                 MLQuestSystem.HandleDeletion(this);
@@ -3683,6 +3673,17 @@ namespace Server.Mobiles
         {
             CreatureEvents.CreatureDeletedEvent(this);
 
+            // Both registries are keyed by the master, which is cleared below.
+            if (IsAnimatedDead)
+            {
+                AnimateDeadSpell.Unregister(SummonMaster, this);
+            }
+
+            if (SummonMaster != null)
+            {
+                SummonFamiliarSpell.Unregister(SummonMaster, this);
+            }
+
             var m = ControlMaster;
             SetControlMaster(null);
 

Projects/UOContent/Mobiles/PlayerMobile.cs

@@ -3835,6 +3835,35 @@ namespace Server.Mobiles
 
                 Stabled = null;
             }
+
+            if (_allFollowers?.Count > 0)
+            {
+                // Releasing or deleting a follower removes it from _allFollowers.
+                using var followers = PooledRefQueue<BaseCreature>.Create(_allFollowers.Count);
+
+                foreach (var follower in _allFollowers)
+                {
+                    // Escorts and hirelings notice a deleted master and walk off on their own.
+                    if (follower is BaseCreature bc and not (BaseEscortable or BaseHire))
+                    {
+                        followers.Enqueue(bc);
+                    }
+                }
+
+                while (followers.Count > 0)
+                {
+                    var bc = followers.Dequeue();
+                    if (bc.Summoned || bc.IsBonded || bc.IsDeadPet)
+                    {
+                        bc.Delete();
+                    }
+                    else
+                    {
+                        // An unbonded pet goes wild and despawns on the abandoned-pet timer.
+                        bc.ControlOrder = OrderType.Release;
+                    }
+                }
+            }
         }
 
         public override int ComputeMovementSpeed(Direction dir, bool checkTurning = true)