The trauma of the 1995 Mount Vision Fire churns at the center of a new documentary by Belgian artists Frederik Carbon and Katrien Vermeire, called “Sunnyside.” The film, named after a winding road that dead ends on the Inverness Ridge, follows the final months in the lives of the iconoclastic architect Daniel Liebermann and his neighbor, the experimental sound artist Henry “Sandy” Jacobs. The longtime friends died within a month of each other in late…