Test now also asserts the menu is back to its original shape (no random-start button), the initial preview and thumb name match the random pick, Start Puzzle begins exactly that image, and the original 🎲 Random button still randomises the menu preview.
The menu always opened on the first artwork; now imageIndex is randomised right after loadArtwork(), so each visit to the picker shows a different initial puzzle. The existing Random/prev/next buttons are unchanged (previous random-start button reverted in 4f2d299). Test page + CDP driver verify 8 fresh page loads all land on a valid in-range image with its preview loaded, with variety across loads.
Brian Fertig