Mirror the right glove across the palm, not along the fingers

OpenXR's grip +X is normal to the palm but points away from it on the left hand
and into it on the right, which is exactly what makes both grips carry the same
orientation when the hands hold a wheel symmetrically. The fingers therefore run
along -Y on both hands, and it is the geometry across the palm that mirrors.
Building the right hand's fingers on +Y instead left them pointing at the player
while the real hand faced forward.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

aurora-main/tests/cockpit_geometry_test.cpp

@@ -116,8 +116,11 @@ TEST_F(CockpitGeometry, TrackedHandDrawsAGloveAtItsGrip) {
 // thumb, +X out of the palm. So the fingers run along Y (+Y on the right hand,
 // -Y on the left) and close towards +X, never out of the back of the hand.
 TEST_F(CockpitGeometry, GloveFingersRunAlongTheHandAndCloseIntoThePalm) {
+  // Both grips carry the same orientation when the hands hold a wheel symmetrically, so the fingers
+  // run along -Y on both and it is the palm side that mirrors: +X on the left hand, -X on the right.
+  // Building the right hand's fingers on +Y instead pointed them at the player (PC, 2026-09-23).
   for (int side = 0; side < 2; ++side) {
-    const float forward = side == 0 ? -1.0f : 1.0f;
+    const float palmSide = side == 0 ? 1.0f : -1.0f;
     const auto build = [&](float squeeze) {
       AuroraCockpit cockpit{};
       cockpit.nativeWheel = true;
@@ -135,9 +138,9 @@ TEST_F(CockpitGeometry, GloveFingersRunAlongTheHandAndCloseIntoThePalm) {
     const auto measure = [&](const std::vector<Vertex>& vertices) {
       Extent e{};
       for (const auto& vertex : vertices) {
-        e.reach = std::max(e.reach, vertex.position[1] * forward);
-        e.palm = std::max(e.palm, vertex.position[0]);
-        e.back = std::min(e.back, vertex.position[0]);
+        e.reach = std::max(e.reach, -vertex.position[1]);
+        e.palm = std::max(e.palm, vertex.position[0] * palmSide);
+        e.back = std::min(e.back, vertex.position[0] * palmSide);
         e.across = std::max(e.across, std::abs(vertex.position[2]));
       }
       return e;