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>

Native/DecalFilters/StdAfx.h

@@ -0,0 +1,55 @@
+// stdafx.h : include file for standard system include files,
+//      or project specific include files that are used frequently,
+//      but are changed infrequently
+
+#if !defined(AFX_STDAFX_H__011A05A6_F7FE_4B67_8D02_926F1F11C8A8__INCLUDED_)
+#define AFX_STDAFX_H__011A05A6_F7FE_4B67_8D02_926F1F11C8A8__INCLUDED_
+
+#if _MSC_VER > 1000
+#pragma once
+#endif // _MSC_VER > 1000
+
+#define STRICT
+#define _WIN32_WINDOWS 0x0410
+#define _ATL_APARTMENT_THREADED
+
+#pragma warning(disable:4530)
+
+//You may derive a class from CComModule and use it if you want to override
+//something, but do not change the name of _Module
+
+//C Library includes
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <atlbase.h>
+extern CComModule _Module;
+#include <atlcom.h>
+#include <comdef.h>
+
+#include <list>
+#include <vector>
+#include <map>
+
+#if _MSC_VER > 1200 // .NET 
+#include <hash_map>
+#endif
+
+#include <set>
+#include <utility>
+#include <algorithm>
+#include <string>
+#include "DecalFilters.h"
+#include "../Include/VSBridge.h"
+
+#ifdef _CHECKMEM
+#define _ASSERTMEM(a) _ASSERTE(a)
+#else
+#define _ASSERTMEM(a)
+#endif
+
+//{{AFX_INSERT_LOCATION}}
+// Microsoft Visual C++ will insert additional declarations immediately before the previous line.
+
+
+#endif // !defined(AFX_STDAFX_H__011A05A6_F7FE_4B67_8D02_926F1F11C8A8__INCLUDED)