Body step 2.1: climbing, mantling, crawling, legs, playground, 144 Hz

- Step rule + lower-body collider: no walking onto tables, steps <= 0.35 m
- Structural hand strength: two-hand mantle/pull-up works, one hand can't
- Arms aim from the physical shoulder horizontally, keep True Body pose vertically
- Crawl pose, crawl carry, 35 deg slope limit, ground feed-forward ignores
  play-space corrections (fixes a runaway feedback loop)
- Grab static world (climbing), procedural visual legs
- Playground sandbox; menu strength slider, spectator (old drag) and turn toggles
- Physics 144 Hz with interpolation; legacy chase-body spikes pin 90 Hz
- RagdollSpike: 27 phases incl. mantle, pull-up, crawl, ledge drop, ramps

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

scripts/PlayerRig.cs

@@ -38,6 +38,21 @@ public partial class PlayerRig : Node
     private bool _rebuild = true;
 
     public PlayerRagdoll Ragdoll => _ragdoll;
+    public static bool Spectator { get; private set; }
+
+    // Spectator = no body (fly with the old grab-drag movement); leaving it rebuilds the body at
+    // the current pose.
+    public static void SetSpectator(bool on)
+    {
+        Spectator = on;
+        AnchorMoveMode.Enabled = on;
+        if (_instance == null)
+            return;
+        if (on)
+            _instance._ragdoll.Clear();
+        _instance._rebuild = true;
+        GD.Print($"PlayerRig: spectator {(on ? "on" : "off")}");
+    }
 
     public static RigidBody3D GetHandBody(XRController3D controller)
     {
@@ -46,7 +61,7 @@ public partial class PlayerRig : Node
         return _instance._ragdoll.Hand(controller == _instance._left ? 0 : 1);
     }
 
-    public static void SetHeld(XRController3D controller, RigidBody3D prop)
+    public static void SetHeld(XRController3D controller, PhysicsBody3D prop)
     {
         if (_instance != null)
             _instance._ragdoll.SetHeld(controller == _instance._left ? 0 : 1, prop);
@@ -65,7 +80,9 @@ public partial class PlayerRig : Node
             _trueBody.ExternallySolved = true;
             TrueBody.ShowDebug = false;
         }
-        _ragdoll = new PlayerRagdoll { Name = "Ragdoll" };
+        // PlayerRig itself is excluded from physics interpolation (ghosts follow controllers per
+        // frame); the body is simulated, so it interpolates.
+        _ragdoll = new PlayerRagdoll { Name = "Ragdoll", PhysicsInterpolationMode = PhysicsInterpolationModeEnum.On };
         AddChild(_ragdoll);
         BodyProfile.Changed += _ => _rebuild = true;
         for (int i = 0; i < 2; i++)
@@ -93,8 +110,11 @@ public partial class PlayerRig : Node
     {
         float dt = (float)delta;
         BodyProfile profile = BodyProfile.Current;
-        if (profile == null)
+        if (profile == null || Spectator)
+        {
+            _haveLastOrigin = false;
             return;
+        }
 
         // 1. Someone else moved the play space discretely: bring the body along.
         Transform3D origin = _origin.GlobalTransform;