Wire up 1.20.6 structured components to Item and fix GetItemSlot serialization

In 1.20.6+, items use structured components instead of NBT for metadata.
Previously, ReadNextItemSlot parsed the components but never stored them
on the Item instance, leaving DisplayName/Lores/Damage/Enchantments all
empty. GetItemSlot also still used the pre-1.20.6 format (bool + VarInt +
byte + NBT), causing the server to reject any item operation packets.

Changes:

Item.cs:
- Add List<StructuredComponent>? Components field to hold the raw
  component list for round-trip serialization
- DisplayName property: read from CustomNameComponent (with
  ItemNameComponent as fallback) when Components is present
- Lores property: read from LoreNameComponent1206 when Components is
  present
- Damage property: read from DamageComponent when Components is present
- Add EnchantmentList property: read from EnchantmentsComponent (covers
  both normal and StoredEnchantmentsComponent for enchanted books)
- ToFullString(): use EnchantmentList with EnchantmentMapping for display
  when available, fall back to NBT path for older versions
- Add CloneWithCount() method that preserves both NBT and Components

DataTypes.cs - ReadNextItemSlot:
- Assign parsed strcturedComponentsToAdd to item.Components

DataTypes.cs - GetItemSlot:
- Add 1.20.6+ branch: write VarInt(count) + VarInt(itemId) + component
  counts + serialized components (using each component's TypeId and
  Serialize() method)
- Empty slot sends VarInt(0) per the 1.20.6 protocol spec

StructuredComponent.cs:
- Add int TypeId property (default -1) to store the registry type ID
  assigned during parsing, enabling round-trip serialization

StructuredComponentRegistry.cs:
- Set component.TypeId = id after instantiation in ParseComponent()

McClient.cs:
- Replace manual Item constructor calls (new Item(type, count, nbt))
  with Item.CloneWithCount() to preserve Components during inventory
  operations like slot moves, stack splits, and right-click placement

Made-with: Cursor

MinecraftClient/Protocol/Handlers/DataTypes.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
 using System.Text;
@@ -450,15 +450,11 @@ namespace MinecraftClient.Protocol.Handlers
                     }
 
                     for (var i = 0; i < numberofComponentsToRemove; i++)
-                    {
-                        // TODO: Check what this does exactly
-                        ReadNextVarInt(cache); // The type of component to remove
-                    }
-                        
-                    // TODO: Wire up the strctured components in the Item class (extract info, update fields, etc..)
-                    // Use strcturedComponentsToAdd
-                    // Look at: https://wiki.vg/index.php?title=Slot_Data&oldid=19350#Structured_components
-                    
+                        ReadNextVarInt(cache);
+
+                    if (strcturedComponentsToAdd.Count > 0)
+                        item.Components = strcturedComponentsToAdd;
+
                     return item;
                 case >= Protocol18Handler.MC_1_13_Version:
                 {
@@ -1561,17 +1557,44 @@ namespace MinecraftClient.Protocol.Handlers
         /// <returns>Item slot representation</returns>
         public byte[] GetItemSlot(Item? item, ItemPalette itemPalette)
         {
-            // TODO: Wire up Structured components for 1.20.6
-            
             List<byte> slotData = new();
-            if (protocolversion > Protocol18Handler.MC_1_13_Version)
+
+            if (protocolversion >= Protocol18Handler.MC_1_20_6_Version)
             {
-                // MC 1.13 and greater
                 if (item == null || item.IsEmpty)
-                    slotData.AddRange(GetBool(false)); // No item
+                {
+                    slotData.AddRange(GetVarInt(0));
+                }
                 else
                 {
-                    slotData.AddRange(GetBool(true)); // Item is present
+                    slotData.AddRange(GetVarInt(item.Count));
+                    slotData.AddRange(GetVarInt(itemPalette.ToId(item.Type)));
+
+                    if (item.Components != null && item.Components.Count > 0)
+                    {
+                        slotData.AddRange(GetVarInt(item.Components.Count));
+                        slotData.AddRange(GetVarInt(0)); // components to remove
+                        foreach (var component in item.Components)
+                        {
+                            slotData.AddRange(GetVarInt(component.TypeId));
+                            var serialized = component.Serialize();
+                            slotData.AddRange(serialized);
+                        }
+                    }
+                    else
+                    {
+                        slotData.AddRange(GetVarInt(0)); // no components to add
+                        slotData.AddRange(GetVarInt(0)); // no components to remove
+                    }
+                }
+            }
+            else if (protocolversion > Protocol18Handler.MC_1_13_Version)
+            {
+                if (item == null || item.IsEmpty)
+                    slotData.AddRange(GetBool(false));
+                else
+                {
+                    slotData.AddRange(GetBool(true));
                     slotData.AddRange(GetVarInt(itemPalette.ToId(item.Type)));
                     slotData.Add((byte)item.Count);
                     slotData.AddRange(GetNbt(item.NBT));
@@ -1579,13 +1602,10 @@ namespace MinecraftClient.Protocol.Handlers
             }
             else
             {
-                // MC 1.12.2 and lower
                 if (item == null || item.IsEmpty)
                     slotData.AddRange(GetShort(-1));
                 else
                 {
-                    // For 1.8 - 1.12.2 we combine Item Id and Item Data to a single value using: (id << 16) | data
-                    // Thus to get an ID we do a right shift by 16 bits
                     slotData.AddRange(GetShort((short)(itemPalette.ToId(item.Type) >> 16)));
                     slotData.Add((byte)item.Count);
                     slotData.Add((byte)item.Data);

MinecraftClient/Protocol/Handlers/StructuredComponents/Core/StructuredComponent.cs

@@ -8,7 +8,12 @@ public abstract class StructuredComponent(DataTypes dataTypes, ItemPalette itemP
     protected DataTypes DataTypes { get; private set; } = dataTypes;
     protected SubComponentRegistry SubComponentRegistry { get; private set; } = subComponentRegistry;
     protected ItemPalette ItemPalette { get; private set; } = itemPalette;
-    
+
+    /// <summary>
+    /// The registry type ID assigned during parsing, used for round-trip serialization.
+    /// </summary>
+    public int TypeId { get; set; } = -1;
+
     public abstract void Parse(Queue<byte> data);
     public abstract Queue<byte> Serialize();
 }

MinecraftClient/Protocol/Handlers/StructuredComponents/Core/StructuredComponentRegistry.cs

@@ -35,7 +35,8 @@ public abstract class StructuredComponentRegistry(DataTypes dataTypes, ItemPalet
                 var component =
                     Activator.CreateInstance(type, dataTypes, itemPalette, subComponentRegistry) as StructuredComponent 
                     ?? throw new InvalidOperationException($"Could not instantiate a parser for a structured component type {name}");
-                
+
+                component.TypeId = id;
                 component.Parse(data);
                 return component;
             }