Add render graph proof of concept and refactor graphics

Implemented a transient render graph system as a proof of concept, including resource aliasing, pass culling, and typed pass data. Added new project `Ghost.RenderGraph.Concept` targeting `.NET 10.0`.

Refactored graphics-related components:
- Simplified resource state transitions in `RenderingContext`.
- Improved resize handling in `GraphicsTestWindow`.
- Updated `D3D12GraphicsEngine` to streamline frame rendering.
- Enhanced `D3D12ResourceDatabase` and `D3D12SwapChain` for better resource management.

Added detailed documentation:
- `ALIASING.md` explains resource aliasing techniques.
- `API_DESIGN.md` outlines the render graph API design.

Updated solution to include the new render graph project.

Ghost.RenderGraph.Concept/RenderGraphResourceHandle.cs

@@ -0,0 +1,41 @@
+namespace Ghost.RenderGraph.Concept;
+
+public class RenderGraphResourceHandle
+{
+    internal int Id { get; }
+    internal ResourceType Type { get; }
+    internal string Name { get; }
+    internal bool IsImported { get; }
+
+    internal RenderGraphResourceHandle(int id, ResourceType type, string name, bool isImported)
+    {
+        Id = id;
+        Type = type;
+        Name = name;
+        IsImported = isImported;
+    }
+
+    public override string ToString() => Name;
+}
+
+public sealed class RenderGraphTextureHandle : RenderGraphResourceHandle
+{
+    internal TextureDescriptor Descriptor { get; }
+
+    internal RenderGraphTextureHandle(int id, string name, TextureDescriptor descriptor, bool isImported)
+        : base(id, ResourceType.Texture, name, isImported)
+    {
+        Descriptor = descriptor;
+    }
+}
+
+public sealed class RenderGraphBufferHandle : RenderGraphResourceHandle
+{
+    internal BufferDescriptor Descriptor { get; }
+
+    internal RenderGraphBufferHandle(int id, string name, BufferDescriptor descriptor, bool isImported)
+        : base(id, ResourceType.Buffer, name, isImported)
+    {
+        Descriptor = descriptor;
+    }
+}