feat: Moves gumps out of the core (#1916)

> [!Important]
> **Developer Note**
> This code change will **completely move gumps out of the core**


### Summary

- Adds `GetGumps()` convenience which exposes methods to Find/Close/Send multiple gumps. This helper is a performance improvement by eliminating the Dictionary<Player, List> lookup for gumps.

Projects/UOContent/Gumps/VirtualCheckGump.cs

@@ -0,0 +1,248 @@
+/*************************************************************************
+ * ModernUO                                                              *
+ * Copyright 2019-2024 - ModernUO Development Team                       *
+ * Email: hi@modernuo.com                                                *
+ * File: VirtualCheckGump.cs                                             *
+ *                                                                       *
+ * This program is free software: you can redistribute it and/or modify  *
+ * it under the terms of the GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3 of the License, or     *
+ * (at your option) any later version.                                   *
+ *                                                                       *
+ * You should have received a copy of the GNU General Public License     *
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
+ *************************************************************************/
+
+using Server.Items;
+using Server.Network;
+
+namespace Server.Gumps;
+
+public sealed class VirtualCheckGump : Gump, IVirtualCheckGump
+{
+    public static unsafe void Configure()
+    {
+        VirtualCheck.GumpActivator = &Activator;
+    }
+
+    private static VirtualCheckGump Activator(Mobile from, VirtualCheck check) => new(from, check);
+
+    public enum Buttons
+    {
+        Close,
+        Clear,
+        Accept,
+        AllPlat,
+        AllGold
+    }
+
+    private int _plat, _gold;
+
+    public override bool Singleton => true;
+
+    public VirtualCheckGump(Mobile user, VirtualCheck check) : base(50, 50)
+    {
+        User = user;
+        Check = check;
+
+        _plat = Check.Plat;
+        _gold = Check.Gold;
+
+        Closable = true;
+        Disposable = true;
+        Draggable = true;
+        Resizable = false;
+
+        CompileLayout();
+    }
+
+    public Mobile User { get; }
+    public VirtualCheck Check { get; private set; }
+
+    public override void OnServerClose(NetState owner)
+    {
+        base.OnServerClose(owner);
+
+        if (Check?.Deleted == false)
+        {
+            Check.UpdateTrade(User);
+        }
+    }
+
+    public void Close()
+    {
+        User.CloseGump<VirtualCheckGump>();
+
+        if (Check?.Deleted == false)
+        {
+            Check.UpdateTrade(User);
+        }
+        else
+        {
+            Check = null;
+        }
+    }
+
+    public void Send()
+    {
+        if (Check?.Deleted == false)
+        {
+            User.SendGump(this);
+        }
+        else
+        {
+            Close();
+        }
+    }
+
+    public void Refresh(bool recompile)
+    {
+        if (Check?.Deleted != false)
+        {
+            Close();
+            return;
+        }
+
+        if (recompile)
+        {
+            CompileLayout();
+        }
+
+        Close();
+        Send();
+    }
+
+    private void CompileLayout()
+    {
+        if (Check?.Deleted != false)
+        {
+            return;
+        }
+
+        Entries.ForEach(e => e.Parent = null);
+        Entries.Clear();
+
+        AddPage(0);
+
+        AddBackground(0, 0, 400, 160, 3500);
+
+        // Title
+        AddImageTiled(25, 35, 350, 3, 96);
+        AddImage(10, 8, 113);
+        AddImage(360, 8, 113);
+
+        AddHtml(40, 15, 320, 20, $"BANK OF {User.RawName.ToUpper()}".Center(0x2F4F4F));
+
+        // Platinum Row
+        AddBackground(15, 60, 175, 20, 9300);
+        AddBackground(20, 45, 165, 30, 9350);
+        AddItem(20, 45, 3826); // Plat
+        AddLabel(60, 50, 0, User.Account.TotalPlat.ToString("#,0"));
+
+        AddButton(195, 50, 95, 95, (int)Buttons.AllPlat); // ->
+
+        AddBackground(210, 60, 175, 20, 9300);
+        AddBackground(215, 45, 165, 30, 9350);
+        AddTextEntry(225, 50, 145, 20, 0, 0, _plat.ToString(), User.Account.TotalPlat.ToString().Length);
+
+        // Gold Row
+        AddBackground(15, 100, 175, 20, 9300);
+        AddBackground(20, 85, 165, 30, 9350);
+        AddItem(20, 85, 3823); // Gold
+        AddLabel(60, 90, 0, User.Account.TotalGold.ToString("#,0"));
+
+        AddButton(195, 90, 95, 95, (int)Buttons.AllGold); // ->
+
+        AddBackground(210, 100, 175, 20, 9300);
+        AddBackground(215, 85, 165, 30, 9350);
+        AddTextEntry(225, 90, 145, 20, 0, 1, _gold.ToString(), User.Account.TotalGold.ToString().Length);
+
+        // Buttons
+        AddButton(20, 128, 12006, 12007, (int)Buttons.Close);
+        AddButton(215, 128, 12003, 12004, (int)Buttons.Clear);
+        AddButton(305, 128, 12000, 12002, (int)Buttons.Accept);
+    }
+
+    public override void OnResponse(NetState sender, in RelayInfo info)
+    {
+        if (Check?.Deleted != false || sender.Mobile != User)
+        {
+            Close();
+            return;
+        }
+
+        var refresh = false;
+        var updated = false;
+
+        switch ((Buttons)info.ButtonID)
+        {
+            case Buttons.Clear:
+                {
+                    _plat = _gold = 0;
+                    refresh = true;
+                    break;
+                }
+            case Buttons.Accept:
+                {
+                    var platText = info.GetTextEntry(0);
+                    var goldText = info.GetTextEntry(1);
+
+                    if (!int.TryParse(platText, out _plat))
+                    {
+                        User.SendMessage("That is not a valid amount of platinum.");
+                        refresh = true;
+                    }
+                    else if (!int.TryParse(goldText, out _gold))
+                    {
+                        User.SendMessage("That is not a valid amount of gold.");
+                        refresh = true;
+                    }
+                    else
+                    {
+                        var totalPlat = User.Account.TotalPlat;
+                        var totalGold = User.Account.TotalGold;
+
+                        if (totalPlat < _plat || totalGold < _gold)
+                        {
+                            _plat = User.Account.TotalPlat;
+                            _gold = User.Account.TotalGold;
+                            User.SendMessage("You do not have that much currency.");
+                            refresh = true;
+                        }
+                        else
+                        {
+                            Check.Plat = _plat;
+                            Check.Gold = _gold;
+                            updated = true;
+                        }
+                    }
+                    break;
+                }
+            case Buttons.AllPlat:
+                {
+                    _plat = User.Account.TotalPlat;
+                    refresh = true;
+                    break;
+                }
+            case Buttons.AllGold:
+                {
+                    _gold = User.Account.TotalGold;
+                    refresh = true;
+                    break;
+                }
+        }
+
+        if (updated)
+        {
+            User.SendMessage("Your offer has been updated.");
+        }
+
+        if (refresh && Check?.Deleted == false)
+        {
+            Refresh(true);
+            return;
+        }
+
+        Close();
+    }
+}