Coming around the corner just a tad too quickly in her new home last month, Ruby swings to greet a visitor but misses by a few inches. Her muzzle meets the wall in a light smack. “Here we go,” Michelle Harding-Olson says, ready to guide her golden retriever forward past the hallway. Ruby has already corrected and heads toward an outstretched hand. Although the bump provokes a joke from Harding-Olson — “We’re thinking of getting her a nose guard” — it’s one of the few signs that betray Ruby’s blindness. The disability clearly hasn’t affected her social nature, zest or …