On a sunny spring Tuesday, Krista Kranyak zipped around her terra cotta-hued restaurant, Beyond Proof in Boston’s Jamaica Plain neighborhood, taking orders from diners and mixing cocktails at the bar. She shook up one of her best-sellers, with ingredients like rhubarb, ginger, egg white foam and a garnish of edible roses. But the "Abstinence in Bloom" is missing one ingredient: alcohol. It’s one of more than a dozen alcohol-free cocktails on the menu at Beyond Proof.