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/DecalInput/EventAction.h

@@ -0,0 +1,48 @@
+// EventAction.h : Declaration of the cEventAction
+
+#ifndef __EVENTACTION_H_
+#define __EVENTACTION_H_
+
+#include "resource.h"       // main symbols
+#include <DecalInputImpl.h>
+
+/////////////////////////////////////////////////////////////////////////////
+// cEventAction
+class ATL_NO_VTABLE cEventAction : 
+	public CComObjectRootEx<CComSingleThreadModel>,
+	public CComCoClass<cEventAction, &CLSID_EventAction>,
+	public IInputActionImpl< cEventAction >
+{
+public:
+	cEventAction()
+	{
+	}
+
+   long m_nEvent;
+
+   HRESULT onLoad( LPTSTR szData )
+   {
+      // Attempt to convert it to a number
+      return ( ::_stscanf( szData, _T( "%i" ), &m_nEvent ) == 1 ) ? S_OK : E_INVALIDARG;
+   }
+
+DECLARE_REGISTRY_RESOURCEID(IDR_EVENTACTION)
+
+DECLARE_PROTECT_FINAL_CONSTRUCT()
+
+BEGIN_COM_MAP(cEventAction)
+	COM_INTERFACE_ENTRY(IInputAction)
+END_COM_MAP()
+
+// IEventAction
+public:
+   STDMETHOD(Execute)()
+   {
+      CComVariant v;
+      m_pSite->FireEvent( m_nEvent, v );
+
+      return S_OK;
+   }
+};
+
+#endif //__EVENTACTION_H_