Philadelphia-based jewelry designer Steven Singer is so thrilled at the prospect of Taylor Swift and Travis Kelce’s engagement that he’s offering the NFL star a $1 million custom-made ring for the proposal. “I recognize that the most renowned couple globally has an abundance of options when it comes to choosing engagement rings, should they decide to tie the knot,” the owner of Steven Singer Jewelers tells Page Six exclusively. “If they do, I would be honored to help design a truly extraordinary ring exclusively for them.” Singer adds that he has a “deeply personal” reason for wanting to design such a sentimental piece for the couple free of charge. “My…