fix: replace Sleep with proper fence synchronization in minimal test

tests/RHI/D3D12/integration/main_minimal.cpp

@@ -180,6 +180,7 @@ void ExecuteCommandList() {
     void* commandLists[] = { gCommandList.GetCommandList() };
     gCommandQueue.ExecuteCommandLists(1, commandLists);
     gFenceValue += 1;
+    gCommandQueue.Signal(gFence.GetFence(), gFenceValue);
 }
 
 // Begin rendering
@@ -274,6 +275,11 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
             TranslateMessage(&msg);
             DispatchMessage(&msg);
         } else {
+            // Wait for previous frame to complete before resetting
+            if (frameCount > 0) {
+                gFence.Wait(gFenceValue);
+            }
+
             // Reset command list for this frame
             gCommandAllocator.Reset();
             gCommandList.Reset();
@@ -312,9 +318,6 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 
             // Present
             gSwapChain.Present(0, 0);
-            
-            // Add small delay to prevent GPU overload
-            Sleep(10);
         }
     }