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
- Create TEST_SPEC.md with OpenGL test hierarchy and specifications
- Add section and inline comments to main.cpp explaining:
- Window size calculation with AdjustWindowRect
- glFinish before screenshot for GPU sync
- Target frame count warm-up period
- Shutdown order (reverse of initialization)
