refactor(tests): reorganize tests directory to match engine structure

- Created tests/Core/Asset/ with tests for IResource, ResourceTypes, ResourceHandle, ResourceCache, ResourceDependencyGraph, ResourceGUID
- Created tests/Core/IO/ with tests for IResourceLoader, ResourcePath, ResourceFileSystem, FileArchive, ResourcePackage
- Reorganized tests/Resources/ into subdirectories: Texture/, Mesh/, Material/, Shader/, AudioClip/
- Added CMakeLists.txt for each new test subdirectory
- Fixed Material.h missing ResourceManager.h include (lost during engine refactor)
- tests/Core/CMakeLists.txt updated to include Asset/ and IO/ subdirectories

engine/include/XCEngine/Resources/Material/Material.h

@@ -1,14 +1,14 @@
 #pragma once
-#include "IResource.h"
-#include "ResourceHandle.h"
-#include "ResourceManager.h"
-#include "Texture.h"
-#include "Shader.h"
-#include "../Containers/HashMap.h"
-#include "../Core/Types.h"
-#include "../Math/Vector2.h"
-#include "../Math/Vector3.h"
-#include "../Math/Vector4.h"
+#include <XCEngine/Core/Asset/IResource.h>
+#include <XCEngine/Core/Asset/ResourceHandle.h>
+#include <XCEngine/Core/Asset/ResourceManager.h>
+#include <XCEngine/Resources/Texture/Texture.h>
+#include <XCEngine/Resources/Shader/Shader.h>
+#include <XCEngine/Core/Containers/HashMap.h>
+#include <XCEngine/Core/Types.h>
+#include <XCEngine/Core/Math/Vector2.h>
+#include <XCEngine/Core/Math/Vector3.h>
+#include <XCEngine/Core/Math/Vector4.h>
 #include <cstring>
 
 namespace XCEngine {