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/RHI/IGraphicsEngine.cs

@@ -7,6 +7,11 @@ public interface IGraphicsEngine : IDisposable
         get;
     }
 
+    public IResourceDatabase ResourceDatabase
+    {
+        get;
+    }
+
     public IResourceAllocator ResourceAllocator
     {
         get;
@@ -27,4 +32,14 @@ public interface IGraphicsEngine : IDisposable
     /// <param name="desc">Swap chain description</param>
     /// <returns>A new swap chain instance</returns>
     public ISwapChain CreateSwapChain(SwapChainDesc desc);
+
+    /// <summary>
+    /// Begins a new rendering frame, preparing the graphics context for drawing operations.
+    /// </summary>
+    public void BeginFrame();
+
+    /// <summary>
+    /// Completes the current rendering frame and performs any necessary finalization steps.
+    /// </summary>
+    public void EndFrame();
 }