Add Ghost.Nvtt C# wrapper and integrate nvtt texture pipeline

- Introduce full managed C# wrapper for NVIDIA Texture Tools (nvtt) with safe handle classes, idiomatic APIs, and managed callback support.
- Integrate Ghost.Nvtt into Ghost.Editor.Core and Ghost.MicroTest; update TextureAssetHandler to use the new nvtt wrapper for texture compression.
- Add comprehensive end-to-end binding test (NvttBindingTest).
- Refactor D3D12 resource management: add deferred/immediate release APIs, update allocator/database usage, and ensure proper resource cleanup.
- Update project files for new native DLL layout and dependency versions.
- Minor API cleanups: EditorApplication properties, D3D12 input layout, and removal of obsolete code.
- Update shaders, tests, and documentation for new APIs and usage patterns.

src/ThridParty/Ghost.Nvtt/NvttSurfaceSet.cs

@@ -1,6 +1,144 @@
-namespace Ghost.Nvtt
+namespace Ghost.Nvtt;
+
+/// <summary>
+/// Wrapper around an nvtt surface set — a collection of faces and mip levels
+/// loaded from a DDS file or built programmatically.
+/// </summary>
+public sealed unsafe class NvttSurfaceSetHandle : IDisposable
 {
-    public partial struct NvttSurfaceSet
+    private NvttSurfaceSet* _ptr;
+
+    /// <summary>Raw pointer – use only when calling the native API directly.</summary>
+    public NvttSurfaceSet* Ptr => _ptr;
+
+    // -------------------------------------------------------------------------
+    // Construction / destruction
+    // -------------------------------------------------------------------------
+
+    public NvttSurfaceSetHandle() => _ptr = Api.nvttCreateSurfaceSet();
+
+    public void Dispose()
     {
+        if (_ptr != null)
+        {
+            Api.nvttDestroySurfaceSet(_ptr);
+            _ptr = null;
+        }
+    }
+
+    // -------------------------------------------------------------------------
+    // Read-only properties
+    // -------------------------------------------------------------------------
+
+    /// <summary>Texture dimensionality stored in this set.</summary>
+    public NvttTextureType TextureType
+    {
+        get { ThrowIfDisposed(); return Api.nvttSurfaceSetGetTextureType(_ptr); }
+    }
+
+    /// <summary>Number of faces (1 for 2-D / 3-D, 6 for cube maps).</summary>
+    public int FaceCount
+    {
+        get { ThrowIfDisposed(); return Api.nvttSurfaceSetGetFaceCount(_ptr); }
+    }
+
+    /// <summary>Number of mip levels.</summary>
+    public int MipmapCount
+    {
+        get { ThrowIfDisposed(); return Api.nvttSurfaceSetGetMipmapCount(_ptr); }
+    }
+
+    /// <summary>Width of the base (mip 0) image in pixels.</summary>
+    public int Width
+    {
+        get { ThrowIfDisposed(); return Api.nvttSurfaceSetGetWidth(_ptr); }
+    }
+
+    /// <summary>Height of the base (mip 0) image in pixels.</summary>
+    public int Height
+    {
+        get { ThrowIfDisposed(); return Api.nvttSurfaceSetGetHeight(_ptr); }
+    }
+
+    /// <summary>Depth of the base (mip 0) image (1 for 2-D textures).</summary>
+    public int Depth
+    {
+        get { ThrowIfDisposed(); return Api.nvttSurfaceSetGetDepth(_ptr); }
+    }
+
+    // -------------------------------------------------------------------------
+    // Surface access
+    // -------------------------------------------------------------------------
+
+    /// <summary>
+    /// Returns the raw <see cref="NvttSurface"/> pointer for the given face
+    /// and mip level.  The pointer is owned by this surface set – do NOT dispose
+    /// it.
+    /// </summary>
+    public NvttSurface* GetSurfacePtr(int faceId, int mipId, bool expectSigned = false)
+    {
+        ThrowIfDisposed();
+        return Api.nvttSurfaceSetGetSurface(_ptr, faceId, mipId,
+            NvttInterop.ToNvtt(expectSigned));
+    }
+
+    // -------------------------------------------------------------------------
+    // Load / Save
+    // -------------------------------------------------------------------------
+
+    /// <summary>Resets the surface set to an empty state.</summary>
+    public void Reset()
+    {
+        ThrowIfDisposed();
+        Api.nvttResetSurfaceSet(_ptr);
+    }
+
+    /// <summary>Loads from a DDS file.  Returns <c>false</c> on failure.</summary>
+    public bool LoadDDS(string fileName, bool forceNormal = false)
+    {
+        ThrowIfDisposed();
+        Span<byte> buf = stackalloc byte[NvttInterop._MAX_STACK_PATH];
+        var utf8 = NvttInterop.ToUtf8(fileName, buf);
+        fixed (byte* p = utf8)
+        {
+            return NvttInterop.ToBool(
+                Api.nvttSurfaceSetLoadDDS(_ptr, (sbyte*)p,
+                    NvttInterop.ToNvtt(forceNormal)));
+        }
+    }
+
+    /// <summary>Loads from a managed byte array containing DDS data.  Returns <c>false</c> on failure.</summary>
+    public bool LoadDDSFromMemory(ReadOnlySpan<byte> data, bool forceNormal = false)
+    {
+        ThrowIfDisposed();
+        fixed (byte* p = data)
+        {
+            return NvttInterop.ToBool(
+                Api.nvttSurfaceSetLoadDDSFromMemory(_ptr, p, (ulong)data.Length,
+                    NvttInterop.ToNvtt(forceNormal)));
+        }
+    }
+
+    /// <summary>Saves a single face/mip as an image file.  Returns <c>false</c> on failure.</summary>
+    public bool SaveImage(string fileName, int faceId, int mipId)
+    {
+        ThrowIfDisposed();
+        Span<byte> buf = stackalloc byte[NvttInterop._MAX_STACK_PATH];
+        var utf8 = NvttInterop.ToUtf8(fileName, buf);
+        fixed (byte* p = utf8)
+        {
+            return NvttInterop.ToBool(
+                Api.nvttSurfaceSetSaveImage(_ptr, (sbyte*)p, faceId, mipId));
+        }
+    }
+
+    // -------------------------------------------------------------------------
+
+    private void ThrowIfDisposed()
+    {
+        if (_ptr == null)
+        {
+            throw new ObjectDisposedException(nameof(NvttSurfaceSetHandle));
+        }
     }
 }