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.DecalRender/RenderServiceImpl.cs

@@ -0,0 +1,74 @@
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using Decal.Interop.Core;
+using Decal.Interop.Inject;
+using Decal.Interop.Render;
+
+namespace Decal.DecalRender
+{
+    [ComVisible(true)]
+    [Guid("FB3C8286-88ED-4B4D-B413-94B40F346239")]
+    [ClassInterface(ClassInterfaceType.None)]
+    [ComSourceInterfaces("Decal.Interop.Render.IRenderServiceEvents\0\0")]
+    [ProgId("DecalRender.RenderService")]
+    public class RenderServiceImpl : IRenderService, IDecalService, IDecalRender
+    {
+        public event IRenderServiceEvents_DeviceLostEventHandler DeviceLost;
+
+        private object _device;
+        private readonly List<HUDViewImpl> _huds = new List<HUDViewImpl>();
+
+        // IRenderService
+        public object Device => _device;
+
+        public HUDView CreateHUD(ref tagRECT pRegion)
+        {
+            var hud = new HUDViewImpl { Region = pRegion };
+            _huds.Add(hud);
+            return (HUDView)(object)hud;
+        }
+
+        public HUDBackground CreateBackground(ref tagRECT pRegion)
+        {
+            return (HUDBackground)(object)new HUDBackgroundImpl { Region = pRegion };
+        }
+
+        public HUDView EncapsulateHUD(ref tagPOINT Coords, object pSurface)
+        {
+            var region = new tagRECT { left = Coords.x, top = Coords.y };
+            var hud = new HUDViewImpl { Region = region };
+            hud.SetSurface(pSurface);
+            _huds.Add(hud);
+            return (HUDView)(object)hud;
+        }
+
+        public HUDBackground EncapsulateBackground(ref tagPOINT Coords, object pSurface)
+        {
+            var region = new tagRECT { left = Coords.x, top = Coords.y };
+            var bg = new HUDBackgroundImpl { Region = region };
+            bg.SetSurface(pSurface);
+            return (HUDBackground)(object)bg;
+        }
+
+        public void RemoveHUD(HUDView pHUD)
+        {
+            var impl = pHUD as HUDViewImpl;
+            if (impl != null)
+                _huds.Remove(impl);
+        }
+
+        // IDecalService
+        public void Initialize(DecalCore pDecal) { }
+        public void BeforePlugins() { }
+        public void AfterPlugins() { }
+        public void Terminate() { _huds.Clear(); }
+
+        // IDecalRender
+        public void Render2D() { }
+        public void Render3D() { }
+        public void PreReset() { DeviceLost?.Invoke(); }
+        public void PostReset() { }
+        public void ChangeHWND() { }
+        public void ChangeDirectX() { }
+    }
+}