feat: add Graphics module with D3D12 backend and documentation

Graphics Module:
- Add platform abstraction layer (GraphicsPlatformInterface)
- Add unified renderer entry point (Renderer)
- Add D3D12 backend implementation (D3D12Core, D3D12Interface)
- Add TestRenderer for multi-window rendering tests

Documentation:
- Add Graphics渲染架构分析.md
- Add D3D12学习Wiki.md
- Add changelogs directory with per-commit documentation
- Add 20260326-dx12-initial.md for initial framework
- Add 20260326-d3d12-foundation.md for Graphics module

Fixes:
- Resolve header include issues and type redefinition errors

Engine/Graphics/Direct3D12/D3D12CommonHeader.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "CommonHeader.h"
+#include "Graphics\Renderer.h"
+
+// 引入 DirectX Graphics Infrastructure（DXGI）6.0 
+// 头文件，用于访问 DXGI 接口（如 IDXGIFactory6、
+// IDXGIAdapter4 等），支持枚举 GPU、查询显示模式、管理
+// 交换链等底层图形功能
+#include <dxgi1_6.h>
+// 引入 Direct3D 12 头文件，提供 D3D12 API 接口，
+// 用于创建渲染管线、管理资源与 GPU 命令
+#include <d3d12.h>
+
+// 引入 Windows Runtime C++ 模板库（WRL）头文件，提供智能指针（如 Microsoft::WRL::ComPtr）
+// 用于简化 COM 对象的生命周期管理
+#include <wrl.h>

Engine/Graphics/Direct3D12/D3D12Core.cpp

@@ -0,0 +1,20 @@
+#include "D3D12Core.h"
+#include "D3D12CommonHeader.h"
+
+namespace XEngine::graphics::d3d12::core{
+namespace{
+
+ID3D12Device8* main_device;
+
+}// anonymous namespace
+bool 
+initialize()
+{
+    // determine which adapter
+	return true;
+}
+void 
+shutdown()
+{
+}
+}// namespace XEngine::graphics::d3d12::core

Engine/Graphics/Direct3D12/D3D12Core.h

@@ -0,0 +1,6 @@
+#pragma once
+
+namespace XEngine::graphics::d3d12::core{
+bool initialize();
+void shutdown();
+}// namespace XEngine::graphics::d3d12

Engine/Graphics/Direct3D12/D3D12Interface.cpp

@@ -0,0 +1,14 @@
+#include "D3D12Interface.h"
+#include "D3D12Core.h"
+#include "Graphics\GraphicsPlatformInterface.h"
+
+namespace XEngine::graphics::d3d12{
+void get_platform_interface(platform_interface& pi)
+{
+	pi.initialize = core::initialize;
+    pi.shutdown = core::shutdown;
+}
+}// namespace XEngine::graphics::d3d12
+
+
+

Engine/Graphics/Direct3D12/D3D12Interface.h

@@ -0,0 +1,9 @@
+#pragma once
+
+namespace XEngine::graphics{
+struct platform_interface;
+}
+
+namespace XEngine::graphics::d3d12{
+void get_platform_interface(platform_interface& gfx);
+}// namespace XEngine::graphics::d3d12

Engine/Graphics/GraphicsPlatformInterface.h

@@ -0,0 +1,11 @@
+#pragma once    
+#include "CommonHeader.h"
+#include "Renderer.h"
+
+namespace XEngine::graphics{
+struct platform_interface{
+    bool(*initialize)(void);
+    void(*shutdown)(void);
+};
+}// namespace XEngine::graphics
+

Engine/Graphics/Renderer.cpp

@@ -0,0 +1,38 @@
+#include "Renderer.h"
+#include "GraphicsPlatformInterface.h"
+#include "Direct3D12/D3D12Interface.h"
+
+namespace XEngine::graphics {
+namespace {
+platform_interface gfx{};
+bool
+set_platform_interface(graphics_platform platform)
+{
+	switch (platform)
+	{
+	case graphics_platform::direct3d12:
+		d3d12::get_platform_interface(gfx);
+		break;
+	case graphics_platform::vulkan:
+		//vulkan::get_platform_interface(gfx);
+		break;
+	case graphics_platform::opengl:
+		//opengl::get_platform_interface(gfx);
+		break;
+	default:
+		return false;
+	}
+	return gfx.initialize();
+}
+}// anonymous namespace
+
+bool initialize(graphics_platform platform)
+{
+	return set_platform_interface(platform);
+}
+
+void shutdown()
+{
+	gfx.shutdown();	
+}
+}// namespace XEngine::graphics

Engine/Graphics/Renderer.h

@@ -0,0 +1,28 @@
+#pragma once
+#include "CommonHeader.h"
+#include "..\Platform\Window.h"
+
+
+namespace XEngine::graphics {
+
+class surface
+{
+};
+
+struct render_surface
+{
+    platform::window window{};
+    surface surface{};
+};
+
+enum class graphics_platform : u32
+{
+    direct3d12 = 0,
+    vulkan = 1,
+    opengl = 2,
+};
+
+bool initialize(graphics_platform platform);    
+void shutdown();
+
+}