Gerrit Cole was built for unique Yankees challenge: ‘Best of the best’

SAN DIEGO — With his back to the harbor and Coronado Island on a picturesque late Southern California morning, Aaron Boone’s face was painted with contentment Wednesday on the Manchester Grand Hyatt balcony. Why wouldn’t he look so satisfied? Tuesday night, the Yankees signed free agent right-hander Gerrit Cole to a record-breaking, nine-year deal for…