Students from the Istituto Alberghiero di Sassari hotel school, led by their trainers, proposed a buffet celebrating Sardinia's culinary heritage at the Italian Embassy in Stockholm, using ingredients from their own territory.     The event is part of the 10th edition of Italian Cuisine Week in the World, scheduled in Stockholm from Nov. 17 to 23. The initiative, held on Nov. 19, was organized in collaboration with the Sassari School Institute Ipsar-Ipseoa through a project called 'Ambassadors