Body step 2.6: landing dip, jump, stick crouch, no flip looking down, smooth view

- Look-down flip: body facing from BodyMath.HeadFacing (visor + crown), robust past vertical;
  stick direction uses it too; crouch lean pitch measured against the facing.
- Landing: falling legs touch down only within their reach, so leg strength stops the body
  below its stance (dip scales with impact, big falls fold the legs). Rise eased so gravity
  can stop it at the stance; legs untuck speed-limited. Fixed the vertical play-space
  correction leaking into ground control's feed-forward (a bounce).
- Jump on right A: countermovement dip + leg push over the stroke (crouch = higher).
- Stick crouch on right stick Y (RagdollDriver.StickCrouch: virtual floor offset).
- Menu summon on left X only.
- XR origin drawn with the bodies' physics interpolation (camera/body desync).
- RagdollSpike: landing/fall/jump/look-down/stick-crouch phases, `-- only=` filter.

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

scripts/WorldPanel.cs

@@ -1,7 +1,7 @@
 using Godot;
 
 // The in-VR menu: a MenuScreen (Godot Control UI in a SubViewport on a thin 0.36x0.24 m
-// panel) showing MainMenu. This node is the XR glue: summon/dismiss with ax_button (A/X),
+// panel) showing MainMenu. This node is the XR glue: summon/dismiss with the LEFT ax_button (X; right A is jump),
 // grip-drag (direct or along the laser), re-orient toward the head, feed both controllers'
 // pointer rays into the screen, click sound + haptics. PARENTED UNDER XROrigin3D (fixed in the
 // player's room; game locomotion carries it).
@@ -114,8 +114,7 @@ public partial class WorldPanel : Node3D
 
     public override void _Process(double delta)
     {
-        PollSummon(_left, 0);
-        PollSummon(_right, 1);
+        PollSummon(_left, 0);   // left X only: right A is jump
         if (Visible)
         {
             UpdateDrag(_left, 0);