Multi-Card Drag Sync and Animation Polish

Staging release — try it at staging.arcanetable.app.

Features

• Multi-card drag syncs to all players - dragging and dropping multiple cards at once now broadcasts a restack event over the network, so everyone sees the same card positions after a drop. Card grid scroll speed has also been tuned down to a more comfortable pace.

Fixes

• Animations snap on interrupt - animations that were cancelled mid-flight (e.g. a card getting moved while already animating) now snap to their destination instead of freezing in place.