fix(kanban): don't export buckets as readonly because that makes it impossible to update them, even from within the store

This fixes a bug where the task on the kanban board would not get updated because the "tasks" property of all buckets were still read only if they were exported once as readonly. This has been unnoticed in the past because the visual representation of the board still perfectly matched what the user was doing and what was saved in the api - just not what was stored in pina.

src/stores/kanban.ts

@@ -370,7 +370,7 @@ export const useKanbanStore = defineStore('kanban', () => {
 	}
 	
 	return {
-		buckets: readonly(buckets),
+		buckets,
 		isLoading: readonly(isLoading),
 	
 		getBucketById,