- Backend: VAPID key generation/storage, push subscription CRUD, notification preferences (reminder time in UTC), background scheduler that checks every minute and sends push notifications to users - Frontend: Settings page with daily reminder toggle and time picker, service worker push event handlers via workbox importScripts, usePushNotifications hook for subscription management - Database: push_subscriptions table, vapid_keys table, reminder columns on user_stats (reminder_enabled, reminder_time, last_notified_date) Implements issue 3mgztv7hflj22 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>