The man on the left is the suspect for a fatal April mugging; at right is his buddyPolice on Wednesday released the above sketch of the mugger who may be responsible for the death of 63-year-old Helen Canafax, and the alleged mugger's pal (right). SF Weekly has written a bit about Canafax, a woman known for her lifelong generosity to the homeless. Several weeks after a violent purse-snatching in front of 680 Folsom Street, she died on May 2 after a blood clot became lodged in her heart; the pulm