riddle of the day 2.0 - Now has calendar, progress and shareable results

What’s new: • A monthly calendar to browse previous puzzles. • Private progress, so returning readers can see what they’ve solved. • Collections by reasoning style: logic, probability, visual traps, strategy, numbers, lateral thinking, and classics. • Shareable results. I’d love to know whether the calendar and progress features make it feel more worth returning to daily.