TEXAS CITY, Texas — When Jason James walks onstage, he declares his love of classic country before he even sings a note. His choice of attire — embroidered suits or pearl-snap shirts and sharply creased slacks — offers a visual tribute to his musical heroes and the traditions they established. But it’s not his looks or style that provide the most convincing evidence of his kinship with other giants of the genre. It’s his sound: the pure, honest voice of a singer who rediscovered his soul when he reawakened his early love of well-crooned waltzes and hook-filled honky-tonkers.