Refactor RHI ResourceView abstraction layer for unified cross-platform interface

- Create unified RHIResourceView base interface with type-specific Initialize methods
- Implement D3D12ResourceView with RTV/DSV/SRV/UAV/CBV support
- Implement OpenGL ResourceView simulation layer using FBO, texture units, and UBO
- Add OpenGLTextureUnitAllocator for managing texture unit bindings
- Add OpenGLUniformBufferManager for UBO binding points
- Add OpenGLFramebuffer for FBO management
- Remove deprecated D3D12 view classes (RenderTargetView, DepthStencilView, etc.)
- Fix ExecuteCommandLists type confusion bug by adding GetNativeHandle to RHICommandList
- Fix test bug where Close() was called before ExecuteCommandLists
- Update all integration tests to use new D3D12ResourceView class
- All tests pass: 144 unit tests + 8 integration tests

tests/RHI/unit/test_command_queue.cpp

@@ -19,11 +19,11 @@ TEST_P(RHITestFixture, CommandQueue_ExecuteCommandLists) {
     ASSERT_NE(cmdList, nullptr);
 
     cmdList->Reset();
-    cmdList->Close();
 
     void* cmdLists[] = { cmdList };
     queue->ExecuteCommandLists(1, cmdLists);
 
+    cmdList->Close();
     cmdList->Shutdown();
     delete cmdList;
     queue->Shutdown();