Elbow: read the hand-suggested angle nearest the current one (fixes side-switching when pointing the controller down: 45 -> 0 switches); point-down spike phase

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

scripts/PhysicsArms.cs

@@ -331,7 +331,14 @@ public partial class PhysicsArms : Node
             handElbow -= dir * handElbow.Dot(dir);
             float confidence = Mathf.Clamp(handElbow.Length() / (0.5f * radius + 1e-4f), 0f, 1f);
             if (handElbow.LengthSquared() > 1e-8f)
-                targetAngle = Mathf.Atan2(handElbow.Dot(refB), handElbow.Dot(refN)) * PoleHandWeight * confidence;
+            {
+                // Read the suggestion as the representation NEAREST the current elbow angle:
+                // pointing the controller down puts it at the ±180° seam, where jitter would
+                // otherwise flip the clamped elbow to the other side.
+                float raw = Mathf.Atan2(handElbow.Dot(refB), handElbow.Dot(refN));
+                raw = _poleAngle[index] + Mathf.Wrap(raw - _poleAngle[index], -Mathf.Pi, Mathf.Pi);
+                targetAngle = raw * PoleHandWeight * confidence;
+            }
         }
         targetAngle = Mathf.Clamp(targetAngle, -PoleMaxAngle, PoleMaxAngle);
         float step = (targetAngle - _poleAngle[index]) * (1f - Mathf.Exp(-delta * PoleSmoothRate));