Matteo Troncone’s life came undone over the course of a few weeks back in 2006. The Mill Valley actor was in the running for a part in “Long Day’s Journey into Night,” only to be cut at the last minute. Then he had a falling out with family, and was almost killed by a Muni bus on Haight Street. “The big kicker,” he said, “was when I got an email from my girlfriend saying she…