Initial commit: Complete open-source Decal rebuild

All 5 phases of the open-source Decal rebuild:

Phase 1: 14 decompiled .NET projects (Interop.*, Adapter, FileService, DecalUtil)
Phase 2: 10 native DLLs rewritten as C# COM servers with matching GUIDs
  - DecalDat, DHS, SpellFilter, DecalInput, DecalNet, DecalFilters
  - Decal.Core, DecalControls, DecalRender, D3DService
Phase 3: C++ shims for Inject.DLL (D3D9 hooking) and LauncherHook.DLL
Phase 4: DenAgent WinForms tray application
Phase 5: WiX installer and build script

25 C# projects building with 0 errors.
Native C++ projects require VS 2022 + Windows SDK (x86).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Managed/Decal.DecalNet/MessageImpl.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Runtime.InteropServices;
+using Decal.Interop.Net;
+
+namespace Decal.DecalNet
+{
+    [ComVisible(true)]
+    [ClassInterface(ClassInterfaceType.None)]
+    public class MessageImpl : IMessage2
+    {
+        private readonly byte[] _rawData;
+        private readonly int _type;
+        private readonly bool _outgoing;
+
+        public MessageImpl(byte[] rawData, bool outgoing)
+        {
+            _rawData = rawData ?? Array.Empty<byte>();
+            _outgoing = outgoing;
+
+            // Message type is the first DWORD in the raw data
+            if (_rawData.Length >= 4)
+                _type = BitConverter.ToInt32(_rawData, 0);
+        }
+
+        public int Type => _type;
+
+        public byte[] RawData => _rawData;
+
+        // Parameterized property - Value takes an index via IDispatch
+        public object Value => null;
+
+        // Parameterized property - Struct takes an index via IDispatch
+        public IMessageMember Struct => null;
+
+        // Parameterized property
+        public byte[] RawValue => _rawData;
+
+        // Parameterized property
+        public string FieldName => string.Empty;
+
+        public int Count => 0;
+
+        public MessageRoot Begin => null;
+    }
+}