Replace the "ride the rim" gear mechanic with instant ball destruction on
contact. Update hazardAt(), resolveTerrain(), and all related tests.
Redesign level 5 ("Watch Out") and level 6 with new terrain layouts
featuring gear hazards, updated ball/pipe/pile positions.
feat(shift): paginate artwork selection and reveal on completion
Add page navigation to artwork cards when there are more than one page,
and fade in the completed artwork over the puzzle after winning.
chore: add 9 new Shift artwork entries
