Keithan Johnson came to TDECU Stadium on Saturday to watch a football game. He left with his first Big 12 offer. The 2028 cornerback from Gilmer, Texas, spent his first visit to Houston doing what corners are coached to do: keeping his eyes on the right place. At halftime, with the Cougars playing a strong first half, he didn’t talk about the scoreboard or the noise. He talked about the guys playing his position. “I just like how disciplined they are with their eyes, keeping their eyes on the receiver’s hips, and when the ball’s in the air, they know how to really break on them,” Johnson…