Sweet-Tea Ribs with Lemony Potato Salad

Ingredients
6 bags black tea (any kind)
1/4 cup plus 2 tablespoons packed light brown sugar
Kosher salt and freshly ground pepper
1 orange
2 racks baby back ribs (about 2 pounds)
2 pounds russet potatoes, peeled and cut into 3/4-inch chunks
1/2 cup mayonnaise
1 tablespoon chopped fresh parsley
1 lemon