feat: 实现 D3D12SwapChain 交换链类

- 添加 D3D12SwapChain.h 头文件
- 实现 IDXGISwapChain3 封装
- 实现 Initialize、Present、Resize 等方法
- 测试通过

engine/include/XCEngine/RHI/D3D12/D3D12SwapChain.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <d3d12.h>
+#include <dxgi1_4.h>
+#include <wrl/client.h>
+
+#include "../Enums.h"
+#include "D3D12Enum.h"
+
+using Microsoft::WRL::ComPtr;
+
+namespace XCEngine {
+namespace RHI {
+
+class D3D12SwapChain {
+public:
+    D3D12SwapChain();
+    ~D3D12SwapChain();
+
+    bool Initialize(IDXGIFactory4* factory, ID3D12CommandQueue* commandQueue, HWND windowHandle, uint32_t width, uint32_t height, uint32_t bufferCount = 2);
+    void Shutdown();
+
+    uint32_t GetCurrentBackBufferIndex() const;
+    ID3D12Resource* GetBackBuffer(uint32_t index) const;
+    void Present(uint32_t syncInterval, uint32_t flags);
+    void Resize(uint32_t width, uint32_t height);
+
+    IDXGISwapChain3* GetSwapChain() const { return m_swapChain.Get(); }
+
+private:
+    ComPtr<IDXGISwapChain3> m_swapChain;
+    ComPtr<ID3D12CommandQueue> m_commandQueue;
+    HWND m_windowHandle;
+    uint32_t m_width;
+    uint32_t m_height;
+    uint32_t m_bufferCount;
+};
+
+} // namespace RHI
+} // namespace XCEngine