My pledge never to have another pet didn’t last a year.     My favorite dog died of congestive heart failure last July. No more pets for me. My heart can’t stand the loss, I pledged. I still shed a tear when I remember Damien, my black Pomeranian.     By February, an empty feeling invaded again. Time for another pet. This time I pledge to save a life.     Never having had a rescue dog, I visited the library for books on dog ownership....