refactor(RHI): 将窗口职责从RHI移到Platform层

- RHIDeviceDesc 删除 windowHandle/width/height/appName
- SwapChainDesc 添加 windowHandle 字段
- RHISwapChain 删除 PollEvents/ShouldClose/SetFullscreen 等窗口相关接口
- OpenGLDevice 删除 CreateRenderWindow，改用 InitializeWithExistingWindow
- 更新所有集成测试使用新API
- 273个单元测试 + 8个集成测试全部通过

tests/RHI/unit/fixtures/RHITestFixture.cpp

@@ -3,6 +3,9 @@
 #include <iostream>
 #include <windows.h>
 
+#include "XCEngine/RHI/D3D12/D3D12Device.h"
+#include "XCEngine/RHI/OpenGL/OpenGLDevice.h"
+
 namespace XCEngine {
 namespace RHI {
 
@@ -26,15 +29,18 @@ void RHITestFixture::SetUp() {
     wc.lpszClassName = L"RHIUnitTestClass";
     RegisterClassExW(&wc);
 
-    HWND hwnd = CreateWindowExW(0, L"RHIUnitTestClass", L"RHIUnitTest", WS_OVERLAPPEDWINDOW,
+    mWindow = CreateWindowExW(0, L"RHIUnitTestClass", L"RHIUnitTest", WS_OVERLAPPEDWINDOW,
         CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, nullptr, nullptr, GetModuleHandle(nullptr), nullptr);
 
-    RHIDeviceDesc desc = {};
-    desc.enableDebugLayer = true;
-    desc.appName = L"RHIUnitTest";
-    desc.windowHandle = hwnd;
-
-    bool initResult = mDevice->Initialize(desc);
+    bool initResult = false;
+    if (GetParam() == RHIType::D3D12) {
+        RHIDeviceDesc desc = {};
+        desc.enableDebugLayer = true;
+        initResult = mDevice->Initialize(desc);
+    } else if (GetParam() == RHIType::OpenGL) {
+        auto* oglDevice = static_cast<OpenGLDevice*>(mDevice);
+        initResult = oglDevice->InitializeWithExistingWindow(mWindow);
+    }
     ASSERT_TRUE(initResult);
 }
 
@@ -44,6 +50,10 @@ void RHITestFixture::TearDown() {
         delete mDevice;
         mDevice = nullptr;
     }
+    if (mWindow) {
+        DestroyWindow(mWindow);
+        mWindow = nullptr;
+    }
 }
 
 } // namespace RHI