[Vuejs]-Making a Copy a Drag and Drop component

It looks in your CodeSandbox that when you drop a card in the sidebar or the board that you fire the function drop. In that function you have access to the card that is dragged.
If I where you I would emit the html element of that card to the app.vue and then place it in the board. Then the placement (append card in target) I would remove that part. So the card is always, and always present in the sidebar.