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.Adapter/Decal.Adapter.Wrappers/Vector4Object.cs

@@ -0,0 +1,79 @@
+namespace Decal.Adapter.Wrappers;
+
+public class Vector4Object
+{
+	private double mW;
+
+	private double mX;
+
+	private double mY;
+
+	private double mZ;
+
+	public double W => mW;
+
+	public double X => mX;
+
+	public double Y => mY;
+
+	public double Z => mZ;
+
+	public Vector4Object(double w, double x, double y, double z)
+	{
+		mW = w;
+		mX = x;
+		mY = y;
+		mZ = z;
+	}
+
+	public override string ToString()
+	{
+		return "{W = " + mW + ", X = " + mX + ", Y = " + mY + ", Z = " + mZ + "}";
+	}
+
+	public override bool Equals(object obj)
+	{
+		if (obj is Vector4Object)
+		{
+			Vector4Object vector4Object = (Vector4Object)obj;
+			if (mW == vector4Object.mW && mX == vector4Object.mX && mY == vector4Object.mY)
+			{
+				return mZ == vector4Object.mZ;
+			}
+			return false;
+		}
+		return false;
+	}
+
+	public bool Equals(Vector4Object obj)
+	{
+		if (obj == null)
+		{
+			return false;
+		}
+		if (mW == obj.mW && mX == obj.mX && mY == obj.mY)
+		{
+			return mZ == obj.mZ;
+		}
+		return false;
+	}
+
+	public override int GetHashCode()
+	{
+		return mW.GetHashCode() ^ mX.GetHashCode() ^ mY.GetHashCode() ^ mZ.GetHashCode();
+	}
+
+	public static bool operator ==(Vector4Object a, Vector4Object b)
+	{
+		if (object.Equals(a, null))
+		{
+			return object.Equals(b, null);
+		}
+		return a.Equals(b);
+	}
+
+	public static bool operator !=(Vector4Object a, Vector4Object b)
+	{
+		return !(a == b);
+	}
+}