refactor: encapsulate frame fence synchronization in CommandQueue

- Add WaitForPreviousFrame() and GetCurrentFrame() to RHICommandQueue interface
- D3D12CommandQueue now manages frame fence internally
- ExecuteCommandLists automatically signals fence after command execution
- OpenGLCommandQueue provides stub implementations for interface compliance
- Minimal test now uses CommandQueue::WaitForPreviousFrame() instead of manual fence

tests/RHI/D3D12/integration/main_minimal.cpp

@@ -42,7 +42,6 @@ D3D12CommandQueue gCommandQueue;
 D3D12SwapChain gSwapChain;
 D3D12CommandAllocator gCommandAllocator;
 D3D12CommandList gCommandList;
-D3D12Fence gFence;
 
 // Render targets
 D3D12Texture gColorRTs[2];
@@ -55,7 +54,6 @@ D3D12DepthStencilView gDSV;
 UINT gRTVDescriptorSize = 0;
 UINT gDSVDescriptorSize = 0;
 int gCurrentRTIndex = 0;
-UINT64 gFenceValue = 0;
 
 // Window
 HWND gHWND = nullptr;
@@ -162,9 +160,6 @@ bool InitD3D12() {
     gCommandAllocator.Initialize(device, CommandQueueType::Direct);
     gCommandList.Initialize(device, CommandQueueType::Direct, gCommandAllocator.GetCommandAllocator());
 
-    // Create fence
-    gFence.Initialize(device, 0);
-
     Log("[INFO] D3D12 initialized successfully");
     return true;
 }
@@ -179,8 +174,6 @@ void ExecuteCommandList() {
     gCommandList.Close();
     void* commandLists[] = { gCommandList.GetCommandList() };
     gCommandQueue.ExecuteCommandLists(1, commandLists);
-    gFenceValue += 1;
-    gCommandQueue.Signal(gFence.GetFence(), gFenceValue);
 }
 
 // Begin rendering
@@ -277,7 +270,7 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
         } else {
             // Wait for previous frame to complete before resetting
             if (frameCount > 0) {
-                gFence.Wait(gFenceValue);
+                gCommandQueue.WaitForPreviousFrame();
             }
 
             // Reset command list for this frame
@@ -324,7 +317,6 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
     // Shutdown
     gCommandList.Shutdown();
     gCommandAllocator.Shutdown();
-    gFence.Shutdown();
     gSwapChain.Shutdown();
     gDevice.Shutdown();