Show HN: PaperMono, e-ink fridge magnet shopping list with mobile web page

PaperMono is a shopping list application for the M5Stack PaperMono e-ink device that syncs with a mobile web app, allowing household members to manage a shared shopping list organized by store aisle. The firmware, written in about 2,400 lines of C++, features a touch-based UI optimized for e-paper displays with efficient partial screen updates, low-power Wi-Fi networking that syncs hourly or on-demand, and offline functionality with queued edits. The system uses a central server to coordinate the list across devices and can automatically sort new items into appropriate aisles using Claude AI.