Body step 2.4: landing, movable ground, playground fixes

- legs brake landings at 4.5 g; vertical support is a rate-limited servo
  (no launch when stepping onto a mantled ledge)
- ground control pushes back on movable ground (seesaw tips under the player)
- playground hinges use absolute paths (joint paths resolve from the joint)
- big props grabbable via surface query; Reset props keeps playground pieces
- spike: landing, seesaw, playground joints/grab, person-like wall climb

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

scripts/PlayerRagdoll.cs

@@ -52,10 +52,11 @@ public partial class PlayerRagdoll : Node3D
     // Ground control (world-space support on the pelvis, only while grounded).
     public const float GroundFrequency = 4f;           // Hz
     public const float GroundDamping = 1f;
-    public const float LegStrength = 2f;               // max support, × body weight
+    public const float LegStrength = 4.5f;             // max support, × body weight (real legs brake a landing at 3–5 g; 2× sank ~0.4 m)
     public const float GroundFriction = 1f;            // horizontal force ≤ this × support
     public const float GroundProbeExtra = 0.3f;        // ground counts while within hip height + this
     public const float MaxStepHeight = 0.35f;
+    public const float MaxRiseSpeed = 1.2f;            // m/s the legs lift the body toward its stance
     public const float MaxSlopeDegrees = 35f;          // steeper ground gives no support (Nimso: "slopes beyond an angle can't be run up")          // higher ground under the hips isn't stood on unless the body got up there
     public const float BracedAirControl = 150f;        // N of horizontal hip carry while airborne but braced on the hands (mantling)
     public const float CrawlCarry = 300f;
@@ -166,6 +167,8 @@ public partial class PlayerRagdoll : Node3D
     private readonly Vector3[] _girdle = new Vector3[2];  // True Body shoulder offset, chest frame
     private float _footY;
     private float _supportGoalY;
+    private RigidBody3D _groundBody;
+    private Vector3 _groundPoint;
     private float _tuckFree, _dt;
     private PhysicsShapeQueryParameters3D _legsQuery;
 
@@ -752,10 +755,13 @@ public partial class PlayerRagdoll : Node3D
         Godot.Collections.Dictionary hit = GetWorld3D().DirectSpaceState.IntersectRay(query);
         bool wasGrounded = Grounded;
         Grounded = false;
+        _groundBody = null;
         if (hit.Count > 0)
         {
             Vector3 point = (Vector3)hit["position"];
             Vector3 normal = (Vector3)hit["normal"];
+            _groundBody = GodotObject.InstanceFromId((ulong)hit["collider_id"]) as RigidBody3D;  // Box3D: "collider" is null
+            _groundPoint = point;
             bool inReach = pos.Y - point.Y < hipAboveFloor + GroundProbeExtra;
             bool steep = normal.Y <= Mathf.Cos(Mathf.DegToRad(MaxSlopeDegrees));
             if (inReach && steep && wasGrounded && point.Y <= _footY + MaxStepHeight)
@@ -806,7 +812,12 @@ public partial class PlayerRagdoll : Node3D
             float w = Mathf.Tau * GroundFrequency;
             Vector3 accel = (goal - pos) * (w * w) + (targetVelocity - Pelvis.LinearVelocity) * (2f * GroundDamping * w);
             Vector3 force = accel * BodyMass;
-            float support = Mathf.Clamp(force.Y + weight, 0f, LegStrength * weight);
+            // Vertical as a rate-limited velocity servo: full leg strength brakes a landing, but
+            // the legs raise the body at most MaxRiseSpeed — they can push, not pull, so a hard push
+            // toward a higher stance (onto a ledge) would otherwise overshoot into a jump.
+            float riseVelocity = Mathf.Clamp((goal.Y - pos.Y) * w, -3f, MaxRiseSpeed) + targetVelocity.Y;
+            float verticalAccel = (riseVelocity - Pelvis.LinearVelocity.Y) * (2f * GroundDamping * w);
+            float support = Mathf.Clamp(verticalAccel * BodyMass + weight, 0f, LegStrength * weight);
             float carry = Mathf.Max(GroundFriction * support, _legsSolid ? 0f : CrawlCarry);
             // Hips held back by an obstacle: lean on it, don't bulldoze — full leg force tipped the
             // body over knee-high boxes and steep slopes (and the riding view tipped with it).
@@ -814,6 +825,10 @@ public partial class PlayerRagdoll : Node3D
                 carry = Mathf.Min(carry, BlockedPush);
             Vector3 horizontal = new Vector3(force.X, 0f, force.Z).LimitLength(carry);
             Pelvis.ApplyCentralForce(horizontal + Vector3.Up * support);
+            // Newton's third law: standing on something movable (seesaw, plank, crate) pushes it
+            // down — the feet aren't physical, so the reaction is applied where the ground ray hit.
+            if (_groundBody != null && IsInstanceValid(_groundBody))
+                _groundBody.ApplyForce(-(horizontal + Vector3.Up * support), _groundPoint - _groundBody.GlobalPosition);
         }
         else if (Braced)
         {