Implemented client-side online accessory sync over existing YGOPro chat flow, so MDPro3 players can see each other’s field/protector/grave/stand/mate and avatar icon/frame in rooms and duels without server changes. Added safe parsing/validation, override-vs-deck source handling, DIY icon support, seat/side mapping, room/duel apply paths, and lifecycle fixes to avoid stale deck data and late UI updates.