What causes my front wheel to twist when I apply the brake?
I'd take a close look at your dropout and your QR skewer.  The rotating disc exerts an upward force on the disc caliper, which tends to want to push the dropout up and away from the axle (or as normally stated, pushes the axle down and out of the dropout).  Some calculations at Jules &amp; James' comprehensive site computes the force generated to be as much as 3800N.

To achieve a 6mm offset at the top of the tire you'd need the axle to move about 1mm within the dropout. Try spinning the wheel in a bike stand with the skewer loose enough to allow free sliding but not wheel ejection, and see if you can replicate the same effect you're seeing out in the real world.