TOKYO — The day before Shinzo Abe was assassinated, Tetsuya Yamagami sent a letter saying that the Unification Church had ruined his life, “destroying my family and driving it into bankruptcy.” Mr. Yamagami’s mother had been a member of the church for over two decades, making prodigious donations over her family’s objections. “It’s no exaggeration to say that my experience with it during that time