Straight up, then level: the helicopter book gets rewritten 715f0f9

Two flight-model matters settled this push, both spotted by pilots watching the traffic instead of flying it:

1. Helicopters now fly like helicopters. The old model popped a few feet off the pad and then climbed while it travelled, rotor disc tilted like it was impatient to be somewhere. Not any more: NAVY 701, the shuttle birds and K-MAN now lift vertically to their cruise altitude — tracking the deck beneath them as they rise — level off, fly the leg at that altitude, and only descend when it’s time to land, gliding down toward the spot on the final leg. Watch the cruiser’s Seahawk on a circuit and you’ll see the whole profile: straight up, level across, slide down, settle.
2. Everyone rolls into the turn now. An audit of every AI pilot in the bay — airliners, bandits, the air wing, the helicopters — found several rolling away from their turns, banked left while heading right. The sign convention is now proven, documented and fixed in all four steering classes: a right turn banks right, everywhere. The pattern over the carrier finally looks like a pattern, not a coin rolling on its edge.