PONOS was the personified Greek spirit of hard labor and toil.   The wide, gravel path snaked through a scrub meadow joining two working-class neighborhoods. Every kid in the neighborhood walked it, back and forth to school. It was shared with men heading to smokestacks visible on the near horizon.   The men funneled onto the path like clockwork, as though gripped by a great magnet—a cycle as precise as the movement of the sun. Some walked alone, others in groups, talking boisterously, occasionally laughing. Their black or stainless-steel lunch buckets, heavy with sandwiches and thermoses,