feat: port retail magic lifecycle and retained spell UI

Complete the retail cast-intent, target, component, enchantment, and busy-state paths; mount the DAT-authored spell bar, spellbook, component book, effects panels, and shared panel lifecycle; and add scoped input plus conformance coverage.

Co-Authored-By: Codex <noreply@openai.com>

src/AcDream.Core.Net/Messages/EnchantmentWireReader.cs

@@ -0,0 +1,115 @@
+using System;
+using System.Buffers.Binary;
+using System.Collections.Generic;
+
+namespace AcDream.Core.Net.Messages;
+
+/// <summary>
+/// Retail <c>Enchantment::UnPack</c> reader shared by PlayerDescription and
+/// the 0x02C2/0x02C4 magic update events. The record is 60 bytes, plus the
+/// optional four-byte spell-set id.
+/// </summary>
+/// <remarks>
+/// Retail reference: <c>CM_Magic::DispatchUI_UpdateEnchantment</c>
+/// (0x006A32F0). Layout cross-checked against ACE
+/// <c>Network/Structure/Enchantment.cs</c>.
+/// </remarks>
+public static class EnchantmentWireReader
+{
+    public static PlayerDescriptionParser.EnchantmentEntry Read(
+        ReadOnlySpan<byte> source,
+        ref int position,
+        PlayerDescriptionParser.EnchantmentBucket bucket = 0)
+    {
+        if (source.Length - position < 60)
+            throw new FormatException("truncated enchantment record");
+
+        ushort spellId = ReadU16(source, ref position);
+        ushort layer = ReadU16(source, ref position);
+        ushort spellCategory = ReadU16(source, ref position);
+        ushort hasSpellSetId = ReadU16(source, ref position);
+        uint powerLevel = ReadU32(source, ref position);
+        double startTime = ReadF64(source, ref position);
+        double duration = ReadF64(source, ref position);
+        uint casterGuid = ReadU32(source, ref position);
+        float degradeModifier = ReadF32(source, ref position);
+        float degradeLimit = ReadF32(source, ref position);
+        double lastDegraded = ReadF64(source, ref position);
+        uint statModType = ReadU32(source, ref position);
+        uint statModKey = ReadU32(source, ref position);
+        float statModValue = ReadF32(source, ref position);
+        uint? spellSetId = hasSpellSetId != 0 ? ReadU32(source, ref position) : null;
+
+        if (!double.IsFinite(startTime)
+            || !double.IsFinite(duration)
+            || !float.IsFinite(degradeModifier)
+            || !float.IsFinite(degradeLimit)
+            || !double.IsFinite(lastDegraded)
+            || !float.IsFinite(statModValue))
+        {
+            throw new FormatException("non-finite enchantment value");
+        }
+
+        return new PlayerDescriptionParser.EnchantmentEntry(
+            spellId, layer, spellCategory, hasSpellSetId, powerLevel,
+            startTime, duration, casterGuid, degradeModifier, degradeLimit,
+            lastDegraded, statModType, statModKey, statModValue, spellSetId,
+            bucket);
+    }
+
+    public static IReadOnlyList<PlayerDescriptionParser.EnchantmentEntry> ReadList(
+        ReadOnlySpan<byte> source,
+        ref int position,
+        PlayerDescriptionParser.EnchantmentBucket bucket = 0)
+    {
+        if (source.Length - position < 4)
+            throw new FormatException("truncated enchantment list count");
+
+        uint count = ReadU32(source, ref position);
+        if (count > 0x4000)
+            throw new FormatException("unreasonable enchantment list count");
+
+        var result = new List<PlayerDescriptionParser.EnchantmentEntry>((int)count);
+        for (uint i = 0; i < count; i++)
+            result.Add(Read(source, ref position, bucket));
+        return result;
+    }
+
+    private static ushort ReadU16(ReadOnlySpan<byte> source, ref int position)
+    {
+        Require(source, position, 2);
+        ushort value = BinaryPrimitives.ReadUInt16LittleEndian(source.Slice(position, 2));
+        position += 2;
+        return value;
+    }
+
+    private static uint ReadU32(ReadOnlySpan<byte> source, ref int position)
+    {
+        Require(source, position, 4);
+        uint value = BinaryPrimitives.ReadUInt32LittleEndian(source.Slice(position, 4));
+        position += 4;
+        return value;
+    }
+
+    private static float ReadF32(ReadOnlySpan<byte> source, ref int position)
+    {
+        Require(source, position, 4);
+        float value = BinaryPrimitives.ReadSingleLittleEndian(source.Slice(position, 4));
+        position += 4;
+        return value;
+    }
+
+    private static double ReadF64(ReadOnlySpan<byte> source, ref int position)
+    {
+        Require(source, position, 8);
+        double value = BinaryPrimitives.ReadDoubleLittleEndian(source.Slice(position, 8));
+        position += 8;
+        return value;
+    }
+
+    private static void Require(ReadOnlySpan<byte> source, int position, int count)
+    {
+        if (position < 0 || source.Length - position < count)
+            throw new FormatException("truncated enchantment record");
+    }
+}