PHILADELPHIA — As Chris Rotz was decorating for Christmas in 2015, he thought of his wife, Kathleen, the woman he knew he was meant to be with when they met for the first time at Doc Watson’s Pub more than 30 years ago. She loved this time of year. They had loved this time of year. But Christmases were different now. That Christmas was the second without Kathleen but Rotz still couldn’t shake this deep longing to give his wife a gift, to show her how much she meant to him, and how she always will. “It was like ‘I miss you, what do you want me to do?'” he said. “And I thought ‘If I can’t buy yo…