0.3.0

Version 0.3.0.
Changes:
+Added shared checklists synced through a Supabase-backed API -- create a list on the website, join it in-game with a share code.
+Added group progress tracking: everyone's held quantity for an item adds up toward one shared target instead of just your own.
+Added a "Join Shared List" screen for entering/leaving a synced list.
+Added ability to remove items from a synced list by right-clicking them (removes it for everyone, not just locally).