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/Include/DecalNetImpl.h

@@ -0,0 +1,87 @@
+// DecalNetImpl.h
+// Declaration of class to help you implement Decal Network Filters
+
+#ifndef __DECALNETIMPL_H
+#define __DECALNETIMPL_H
+
+#include <DecalNet.h>
+
+// The solo network filter does not have any depencies and does not store
+// the INetServices object - clients must implement INetworkFilter::Dispatch
+template< class ImplT >
+class ATL_NO_VTABLE ISoloNetworkFilterImpl
+: public INetworkFilter2
+{
+public:
+   STDMETHOD(Initialize)(INetService *)
+   {
+      return S_OK;
+   }
+
+   STDMETHOD(Terminate)()
+   {
+      return S_OK;
+   }
+
+   STDMETHOD(DispatchServer)(IMessage2 *)
+   {
+      return S_OK;
+   }
+
+   STDMETHOD(DispatchClient)(IMessage2 *)
+   {
+      return S_OK;
+   }
+};
+
+// This version stores the INetService pointer passed during initialization.
+// A network can use this to recall back to the Decal object and get extended
+// state information
+template< class ImplT >
+class ATL_NO_VTABLE INetworkFilterImpl
+: public INetworkFilter2
+{
+public:
+   CComPtr< INetService > m_pService;
+
+   HRESULT onInitialize()
+   {
+      return S_OK;
+   }
+
+   void onTerminate()
+   {
+   }
+
+   STDMETHOD(Initialize)(INetService *pService)
+   {
+      m_pService = pService;
+
+      HRESULT hRes = static_cast< ImplT * >( this )->onInitialize();
+
+      if( FAILED( hRes ) )
+         m_pService.Release();
+
+      return hRes;
+   }
+
+   STDMETHOD(Terminate)()
+   {
+      static_cast< ImplT * >( this )->onTerminate();
+      m_pService.Release();
+
+      return S_OK;
+   }
+
+   STDMETHOD(DispatchServer)(IMessage2 *)
+   {
+      return S_OK;
+   }
+
+   STDMETHOD(DispatchClient)(IMessage2 *)
+   {
+      return S_OK;
+   }
+};
+
+#endif