Drive with bare hands in the cockpit

- With tracked hands on, a hand driving khr/simple_controller with camera-tracked joints is bare:
  latched through wheel_tracking_grace (Meta drops the select action while a hand is lost),
  cleared as soon as a controller's squeeze is back. Its palm joint stands in for the grip and a
  grasp from the middle, ring and little fingers' flexion (0 below 1.2 rad, 1 from 3.0) for the
  squeeze, so closing a hand on the rim takes hold under the wheel's own press and release. The
  grasp never reaches the game's buttons.
- In a cockpit race a bare hand holding the wheel holds the gas (A / South) and a pinch from a free
  bare hand uses an item (Z / L) once the hand has been off the wheel for 0.15 s. Only while the
  game has the remote's pointer off: KPAD publishes the game's pointer switch for the VR remote,
  so the pause menu and the results keep a right pinch as A. The pacing thread logs each change,
  to confirm on the headset that MKW turns the pointer off while driving.
- A held bare hand keeps its last joints drawn through a short loss; bare hands get no haptics.
  The headset panel's readout shows grasp, hold and pinch. Docs: OPENXR.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/app/src/main/res/values/strings.xml

@@ -534,7 +534,7 @@
     <string name="vr_hand_steering">Hand steering</string>
     <string name="vr_hand_steering_helper">In the cockpit, squeeze a grip near the steering wheel or handlebar to grab it, and turn it to steer. Releasing both grips gives steering back to the stick. Hand steering by heurazy.</string>
     <string name="vr_hand_tracking">Tracked hands</string>
-    <string name="vr_hand_tracking_helper">The cockpit hands follow your own. Holding the controllers, the fingers follow their touch sensors; put the controllers down and the headset\'s cameras track your hands. Needs hand tracking on in the headset\'s settings.</string>
+    <string name="vr_hand_tracking_helper">The cockpit hands follow your own. Holding the controllers, the fingers follow their touch sensors. Put the controllers down to drive with bare hands: close a hand on the wheel to hold it, which also holds the gas; pinch with a free hand to use an item; pinch with your left palm facing you to pause. In menus, a right pinch is A. Choose Automatic drift. Needs hand tracking on in the headset\'s settings.</string>
     <string name="vr_lean_back">Lean back angle</string>
     <string name="vr_lean_back_helper">Tilts the race view back for playing reclined. 0 applies no tilt.</string>