PASS: all six 4K originals remain intact; 66 full-frame/aspect-ratio geometry checks passed.
PASS: previews use Uniform; install/manual/rotation paths use Fit, with an Apply screen fit action.
Resolution cases: 1920x1080, 2560x1440, 3840x2160, 1366x768, 1280x1024, 1720x1080, 3440x1440, 3840x1600, 5120x1440, 1080x1920, 2160x3840
Geometric validation models documented Windows Fit behavior. Live Windows desktop refresh is not tested on this Linux host.
