Refactor GPU resource management and rendering pipeline

- Introduced `Handle<T>` and `Identifier<T>` for lightweight, strongly-typed resource identifiers.
- Replaced `BitSet` with `UnsafeBitSet` for improved performance and memory safety.
- Refactored `Mesh` and `Material` into `MeshClass` and `MaterialClass` for better GPU resource handling.
- Added `D3D12ResourceDatabase` to centralize GPU resource tracking and lifecycle management.
- Updated `D3D12ShaderCompiler` to load shaders from disk and dynamically populate constant buffers and textures.
- Enhanced `ICommandBuffer` with new upload operations for buffers and textures.
- Refactored `Vertex` struct for simplified memory layout and better performance.
- Updated `MeshBuilder` and rendering logic to align with new resource and shader structures.
- Added `BindlessDescriptor` support to `TextureHandle` and `BufferHandle`.
- Removed unused classes and performed general cleanup.
- Updated unit tests and demos to reflect the new architecture.

Ghost.Graphics/D3D12/D3D12Renderer.cs

@@ -169,7 +169,7 @@ public unsafe class D3D12Renderer : IRenderer
 
     private void RenderScene(IRenderTarget target, ICommandBuffer cmd)
     {
-        var clearColor = new Color16 { r = 1.0f, g = 0.0f, b = 1.0f, a = 1.0f };
+        var clearColor = new Color128 { r = 1.0f, g = 0.0f, b = 1.0f, a = 1.0f };
 
         cmd.BeginRenderPass(target, clearColor);
 
@@ -207,7 +207,7 @@ public unsafe class D3D12Renderer : IRenderer
         // 3. Apply post-processing effects (tone mapping, gamma correction, etc.)
 
         // For now, just clear the destination (this should be replaced with actual blit)
-        var clearColor = new Color16 { r = 0.0f, g = 0.0f, b = 0.0f, a = 1.0f };
+        var clearColor = new Color128 { r = 0.0f, g = 0.0f, b = 0.0f, a = 1.0f };
         cmd.BeginRenderPass(destination, clearColor);
         cmd.EndRenderPass();