JKL Pesto Pork and Veggie Roast

Name: JKL Pesto Pork and Veggie Roast
Ingredients: 5 cloves garlic; 3 teaspoons coarse sea salt, divided; 3 teaspoons freshly ground black pepper, divided; 1/4 teaspoon cayenne pepper; 1 tablespoon fresh rosemary leaves; 3 teaspoons sugar; 1 (3-pound) pork loin roast, trussed; 2 onions, quartered; 2 zucchini, cut into 8 half-moon pieces; 2 summer squash, cut into 8 half-moon pieces; 2 carrots, washed and cut into 8 pieces; 3 tomatoes, quartered; 2 medium red potatoes, quartered; 1 cup store-bought pesto; 1 tablespoon grapeseed oil; 1/2 cup white wine, plus more if needed; 3/4 cup chicken stock, plus more if needed; 3 tablespoons butter