feat: 实现 D3D12PipelineState 并替换到 tests/D3D12

- 添加 D3D12PipelineState.h/cpp
- 全局变量 gPipelineState
- 使用 D3D12PipelineState::Initialize 替代原生 CreateGraphicsPipelineState
- 测试通过

engine/src/RHI/D3D12PipelineState.cpp

@@ -0,0 +1,26 @@
+#include "XCEngine/RHI/D3D12/D3D12PipelineState.h"
+
+namespace XCEngine {
+namespace RHI {
+
+D3D12PipelineState::D3D12PipelineState() {
+}
+
+D3D12PipelineState::~D3D12PipelineState() {
+    Shutdown();
+}
+
+bool D3D12PipelineState::Initialize(ID3D12Device* device, const D3D12_GRAPHICS_PIPELINE_STATE_DESC& desc) {
+    HRESULT hResult = device->CreateGraphicsPipelineState(&desc, IID_PPV_ARGS(&m_pipelineState));
+    if (FAILED(hResult)) {
+        return false;
+    }
+    return true;
+}
+
+void D3D12PipelineState::Shutdown() {
+    m_pipelineState.Reset();
+}
+
+} // namespace RHI
+} // namespace XCEngine