Off the top, I would set up a cash account as "Employee Program Gift Cards". I would set up an income category for "Gift Card Income" tied to an appropriate tax line. As applicable, I'd enter deposits to that account tied to that category. When used, I'd expense from the accounts for the items and categories bought.
You might want to experiment as to whether you track individual cards or not. For me, might depend on whether these are $5 or $500 cards. Tags or memo fields come to mind as card tracking tools.
