The engine unit tests share one process, and two colour-management tests
switched the process-wide Color Settings (the working RGB space to the wide
gamut profile, Black Point Compensation off) for a moment. Any test that
showed or rendered a colour at that moment saw it through the wrong profile:
clicking_an_image_samples_its_pixel read #008181 instead of #008080.
- Move the two tests that change the Color Settings to their own test
binary (crates/engine/tests/color_settings.rs), so no unit test can see
non-default settings.
- The image-sampling test compares the stored colour, not its display hex.
- every_command_survives_empty_params toggles the process-wide proof view
(Proof Colors, Overprint Preview, Separations), so it now takes the
colour-management test lock like the tests that read that view.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>