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/Base/GumpSystem.IncomingPackets.cs

@@ -0,0 +1,198 @@
+/*************************************************************************
+ * ModernUO                                                              *
+ * Copyright 2019-2023 - ModernUO Development Team                       *
+ * Email: hi@modernuo.com                                                *
+ * File: IncomingGumpPackets.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.Diagnostics;
+using Server.Engines.Virtues;
+using Server.Exceptions;
+using Server.Mobiles;
+using Server.Network;
+using System;
+using System.Buffers;
+using System.Buffers.Binary;
+using System.Diagnostics;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace Server.Gumps;
+
+public static partial class GumpSystem
+{
+    public static void DisplayGumpResponse(NetState state, SpanReader reader)
+    {
+        var serial = (Serial)reader.ReadUInt32();
+        var typeId = reader.ReadInt32();
+        var buttonId = reader.ReadInt32();
+
+        BaseGump baseGump = null;
+
+        foreach (var g in GetAll(state))
+        {
+            if (g.Serial != serial || g.TypeID != typeId)
+            {
+                continue;
+            }
+
+            baseGump = g;
+            break;
+        }
+
+        if (baseGump != null)
+        {
+            if (baseGump is Gump gump)
+            {
+                var buttonExists = buttonId == 0; // 0 is always 'close'
+
+                if (!buttonExists)
+                {
+                    foreach (var e in gump.Entries)
+                    {
+                        if ((e as GumpButton)?.ButtonID == buttonId)
+                        {
+                            buttonExists = true;
+                            break;
+                        }
+
+                        if ((e as GumpImageTileButton)?.ButtonID == buttonId)
+                        {
+                            buttonExists = true;
+                            break;
+                        }
+                    }
+                }
+
+                if (!buttonExists)
+                {
+                    state.LogInfo("Invalid gump response, disconnecting...");
+                    var exception = new InvalidGumpResponseException($"Button {buttonId} doesn't exist");
+                    exception.SetStackTrace(new StackTrace());
+                    NetState.TraceException(exception);
+                    return;
+                }
+            }
+
+            var switchCount = reader.ReadInt32();
+
+            if (switchCount < 0 || switchCount > baseGump.Switches)
+            {
+                state.LogInfo("Invalid gump response, disconnecting...");
+                var exception = new InvalidGumpResponseException($"Bad switch count {switchCount}");
+                exception.SetStackTrace(new StackTrace());
+                NetState.TraceException(exception);
+                return;
+            }
+
+            int switchByteCount = switchCount * 4;
+
+            // Read all the integers
+            ReadOnlySpan<int> switchBlock =
+                MemoryMarshal.Cast<byte, int>(reader.Buffer.Slice(reader.Position, switchByteCount));
+
+            reader.Seek(switchByteCount, SeekOrigin.Current);
+
+            scoped ReadOnlySpan<int> switches;
+
+            // Swap the endianness if necessary
+            if (BitConverter.IsLittleEndian)
+            {
+                Span<int> reversedSwitches = stackalloc int[switchCount];
+                BinaryPrimitives.ReverseEndianness(switchBlock, reversedSwitches);
+                switches = reversedSwitches;
+            }
+            else
+            {
+                switches = switchBlock;
+            }
+
+            var textCount = reader.ReadInt32();
+            if (textCount < 0 || textCount > baseGump.TextEntries)
+            {
+                state.LogInfo("Invalid gump response, disconnecting...");
+                var exception = new InvalidGumpResponseException($"Bad text entry count {textCount}");
+                exception.SetStackTrace(new StackTrace());
+                NetState.TraceException(exception);
+                return;
+            }
+
+            Span<ushort> textIds = stackalloc ushort[textCount];
+            Span<Range> textFields = stackalloc Range[textCount];
+
+            var textOffset = reader.Position;
+            for (var i = 0; i < textCount; i++)
+            {
+                var textId = reader.ReadUInt16();
+                var textLength = reader.ReadUInt16();
+
+                if (textLength > 239)
+                {
+                    state.LogInfo("Invalid gump response, disconnecting...");
+                    var exception = new InvalidGumpResponseException($"Text entry {i} is too long ({textLength})");
+                    exception.SetStackTrace(new StackTrace());
+                    NetState.TraceException(exception);
+                    return;
+                }
+
+                textIds[i] = textId;
+                var offset = reader.Position - textOffset;
+                var length = textLength * 2;
+                textFields[i] = offset..(offset + length);
+                reader.Seek(length, SeekOrigin.Current);
+            }
+
+            var textBlock = reader.Buffer.Slice(textOffset, reader.Position - textOffset);
+
+            Remove(state, baseGump);
+
+            var prof = GumpProfile.Acquire(baseGump.GetType());
+
+            prof?.Start();
+
+            var relayInfo = new RelayInfo(
+                buttonId,
+                switches,
+                textIds,
+                textFields,
+                textBlock
+            );
+            baseGump.OnResponse(state, relayInfo);
+
+            prof?.Finish();
+        }
+
+        if (typeId == 461)
+        {
+            // Virtue gump
+            var switchCount = reader.Remaining >= 4 ? reader.ReadInt32() : 0;
+
+            if (buttonId == 1 && switchCount > 0)
+            {
+                var beheld = World.FindEntity<PlayerMobile>((Serial)reader.ReadUInt32());
+
+                if (beheld != null)
+                {
+                    VirtueGump.RequestVirtueGump((PlayerMobile)state.Mobile, beheld);
+                }
+            }
+            else
+            {
+                var beheld = World.FindMobile(serial);
+
+                if (beheld != null)
+                {
+                    VirtueGump.RequestVirtueItem((PlayerMobile)state.Mobile, beheld, buttonId);
+                }
+            }
+        }
+    }
+}