React Transfer List (Select + Move Between Two Lists)

Challenge summary

Build a React transfer list UI with two panels and checkbox selection. Preserve item order, clear selection after transfer, and disable buttons when nothing is selected.

What you'll practice

• Render two lists: Top and Bottom.
• Provide two transfer buttons between lists: "↓" moves selected Top items to Bottom; "↑" moves selected Bottom items to Top.
• Disable "↓" when no Top items are selected; disable "↑" when no Bottom items are selected.
• After transfer, moved items must be unselected in the destination list.
• Preserve item order within each list (append moved items to the end of destination list).

What Premium unlocks

Premium unlocks the runnable workspace, behavioral checks, implementation walkthrough, and edge-case discussion.