feat: Fixes spawner bugs with position finding, Adds [ShowSpawnerBorders (#2297)

### Summary

- Fixes BaseSpawner and Spawner bugs.
- Adds [ShowSpawnerBorders to see the spawn bounds.

Projects/UOContent/Items/Misc/ProjectedItem.cs

@@ -0,0 +1,189 @@
+using System;
+using System.Collections.Generic;
+using ModernUO.Serialization;
+using Server.Collections;
+using Server.Network;
+
+namespace Server.Items;
+
+[SerializationGenerator(0)]
+public partial class ProjectedItem : Item
+{
+    private static readonly HashSet<ProjectedItem> _active = [];
+    private static Timer _timer;
+
+    [SerializedCommandProperty(AccessLevel.GameMaster)]
+    [SerializableField(0)]
+    private int _effectItemId;
+
+    [SerializedCommandProperty(AccessLevel.Developer)]
+    [SerializableField(1)]
+    private AccessLevel _minimumVisible;
+
+    private bool _oldVisible;
+
+    [Constructible]
+    public ProjectedItem(int effectItemId) : base(1)
+    {
+        Movable = false;
+        Visible = false;
+        _effectItemId = effectItemId;
+    }
+
+    public override bool HandlesOnMovement => true;
+
+    public override bool CanSeeStaffOnly(Mobile from) => from.AccessLevel >= _minimumVisible;
+
+    public override void ProcessDelta()
+    {
+        if (_oldVisible != Visible)
+        {
+            Timer.DelayCall(
+                TimeSpan.Zero,
+                i =>
+                {
+                    i.ItemID = i.Visible ? i._effectItemId : 1;
+                    i._oldVisible = i.Visible;
+                    i.Activate();
+                },
+                this
+            );
+        }
+
+        base.ProcessDelta();
+    }
+
+    public override void SendInfoTo(NetState ns, ReadOnlySpan<byte> world = default)
+    {
+        base.SendInfoTo(ns, world);
+
+        var m = ns.Mobile;
+        if (m != null && !Visible && m.AccessLevel >= _minimumVisible && !_active.Contains(this))
+        {
+            Activate();
+        }
+    }
+
+    public override void OnLocationChange(Point3D oldLocation)
+    {
+        base.OnLocationChange(oldLocation);
+        Activate();
+    }
+
+    public override void OnMapChange()
+    {
+        base.OnMapChange();
+        Activate();
+    }
+
+    public override void OnDelete()
+    {
+        Deactivate();
+        base.OnDelete();
+    }
+
+    [AfterDeserialization]
+    private void AfterDeserialization()
+    {
+        _oldVisible = Visible;
+    }
+
+    public override void OnMovement(Mobile m, Point3D oldLocation)
+    {
+        base.OnMovement(m, oldLocation);
+
+        if (!Visible && m.AccessLevel >= _minimumVisible && !_active.Contains(this))
+        {
+            Activate();
+        }
+    }
+
+    private void Activate()
+    {
+        if (!_active.Add(this))
+        {
+            return;
+        }
+
+        if (_timer == null)
+        {
+            _timer = Timer.DelayCall(TimeSpan.Zero, TimeSpan.FromSeconds(1.0), OnTick);
+        }
+        else if (!_timer.Running)
+        {
+            _timer.Interval = TimeSpan.FromSeconds(1.0);
+            _timer.Start();
+        }
+    }
+
+    private void Deactivate()
+    {
+        if (_active.Remove(this) && _active.Count == 0)
+        {
+            _timer?.Stop();
+        }
+    }
+
+    private static void OnTick()
+    {
+        using var queue = PooledRefQueue<Item>.Create();
+        foreach (var item in _active)
+        {
+            if (!item.SendEffect())
+            {
+                queue.Enqueue(item);
+            }
+        }
+
+        while (queue.Count > 0)
+        {
+            _active.Remove(queue.Dequeue() as ProjectedItem);
+        }
+
+        if (_active.Count == 0)
+        {
+            _timer?.Stop();
+        }
+    }
+
+    protected virtual bool SendEffect()
+    {
+        if (_oldVisible)
+        {
+            return false;
+        }
+
+        var found = false;
+        Span<byte> buffer = new byte[OutgoingEffectPackets.HuedEffectLength].InitializePacket();
+        OutgoingEffectPackets.CreateHuedEffect(
+            buffer,
+            EffectType.FixedXYZ,
+            Serial,
+            Serial,
+            _effectItemId,
+            Location,
+            Location,
+            1,
+            20,
+            true,
+            false,
+            Hue - 1,
+            3
+        );
+
+        foreach (var ns in GetClientsInRange(GetMaxUpdateRange()))
+        {
+            found = true;
+            var from = ns.Mobile;
+            if (ns.CannotSendPackets() || from == null || from.AccessLevel < _minimumVisible)
+            {
+                continue;
+            }
+
+            from.ProcessDelta();
+            ns.Send(buffer);
+        }
+
+        return found;
+    }
+}