New `change_item_position` mutation

🏷️ API version: 2025-10

You can now change an item's position on the same board using the new change_item_position mutation. The following example moves 1234567890 after item 9876543210.

mutation { 
 change_item_position (
  item_id: 1234567890,
  relative_to: 9876543210,
  position_relative_method: after_at
 ) {
  id
  group {
   id
  }
 }
}