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/Inject/PluginAdapterV1.cpp

@@ -0,0 +1,74 @@
+// PluginAdapterV1.cpp : Implementation of cPluginAdapterV1
+#include "stdafx.h"
+#include "Inject.h"
+#include "PluginAdapterV1.h"
+
+#include "Manager.h"
+
+/////////////////////////////////////////////////////////////////////////////
+// cPluginAdapterV1
+
+STDMETHODIMP cPluginAdapterV1::Initialize(IPluginSite2 *pSite2)
+{
+   // First retreive the Inject service
+   CComPtr< IDecal > pDecal;
+   pSite2->get_Decal ( &pDecal );
+
+   CComPtr< IInjectService > pInject;
+   HRESULT hRes = pDecal->get_Object ( _bstr_t ( _T( "services\\DecalPlugins.InjectService" ) ),
+      __uuidof ( IInjectService ), reinterpret_cast< LPVOID * > ( &pInject ) );
+
+   if ( FAILED ( hRes ) )
+      return hRes;
+
+   // Try to initialize our plugin
+   CComPtr< IPlugin > pPlugin;
+   hRes = m_pUnkPlugin->QueryInterface ( &pPlugin );
+   if ( FAILED ( hRes ) )
+      return hRes;
+
+   CComPtr< IPluginSite > pSite;
+   pInject->get_Site ( &pSite );
+
+   try
+   {
+      pPlugin->Initialize ( pSite, 0 );
+   }
+   catch ( ... )
+   {
+      return E_FAIL;
+   }
+
+   pInject->InitPlugin ( m_pUnkPlugin );
+
+   // Store the site if everything is OK
+   m_pSite2 = pSite2;
+   return S_OK;
+}
+
+STDMETHODIMP cPluginAdapterV1::Terminate()
+{
+   CComPtr< IPlugin > pPlugin;
+
+   if ( SUCCEEDED ( m_pUnkPlugin->QueryInterface ( &pPlugin ) ) )
+      pPlugin->Terminate ();
+
+   m_pUnkPlugin.Release ();
+   m_pSite2.Release ();
+
+   return S_OK;
+}
+
+STDMETHODIMP cPluginAdapterV1::CreateInstance(IDecalEnum *pEnum, REFIID riid, LPVOID *ppvItf)
+{
+   CLSID clsidV1;
+   HRESULT hRes = pEnum->get_ComClass ( &clsidV1 );
+   if ( FAILED( hRes ) )
+      return hRes;
+
+   hRes = ::CoCreateInstance ( clsidV1, NULL, CLSCTX_INPROC_SERVER, IID_IUnknown, reinterpret_cast< LPVOID * > ( &m_pUnkPlugin ) );
+   if ( FAILED ( hRes ) )
+      return hRes;
+
+   return static_cast< IDecalSurrogate * > ( this )->QueryInterface ( riid, ppvItf );
+}