Edit logged food: macro inputs render white text on white background #3

User-reported. In frontend/src/components/MealList.jsx the per-component "Edit" grid (~L867-917) and the simple-food "Edit Manually" grid (~L1025-1075) have ten <input type="number"> with className="... border text-xs sm:text-sm text-white" and no background class. Tailwind preflight leaves number inputs with the browser's white background, so values are invisible.

Fix: add bg-black border-[#1a1a1a] (match ${colors.inputBg} used by other inputs at ~L757/L957, or use the shared .input class). Consider adding color-scheme: dark to body in index.css so native spinners match.

Acceptance: edit fields readable; existing MealList/MealForm tests pass; add a test asserting the edit inputs carry a dark bg class.