Key points:\n- restore the tests tree removed by bc47e6e\n- capture current editor workspace, scene, and docs reshuffle changes\n- keep local cloud.nvdb resources ignored from this commit
- Add OpenGL_Minimal integration test using Win32 native API + glad
- Copy run_integration_test.py and compare_ppm.py from D3D12
- Create minimal/main.cpp with red clear color (matching D3D12)
- Generate GT.ppm golden template for 1280x720 red window
- Add VertexArray_Bind_MultipleAttributes unit test
- Update integration/CMakeLists.txt to build OpenGL_Minimal target
