Flick the bare hands for a trick

- A bare hand already feeds no Wii Remote motion (camera-tracked poses are too noisy to
  differentiate twice). In a cockpit race, both hands on the wheel rising together or a free bare
  hand rising fast now plays one shake on the remote's accelerometer: 150 ms, so the guest sees it
  on at least three frames, one cycle up to +2 g and down to the -3.6 g limit, as Dolphin's
  emulated shake does. A turn (one hand up, the other down) never flicks, nor does a lone hand on
  the wheel; a rise must last three samples and cover 5 cm within 150 ms, tracking jumps reset it,
  and flicks are 0.5 s apart. Wii Remote presentation only.
- debug.wiicompiled.inject <n>:flick plays the same shake, with the controllers or unattended, to
  tune it apart from the gesture. Docs: OPENXR.md, docs/quest-port.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 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_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; flick your hands up for a trick; 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>