Body physics Stage 1: PhysicsTorso chase chest (30 kg PD + yaw servo), collision layers reworked (3=body, 4=hands, no self-collision), BodyRig visual-only, BodySpike regression (PASS 3x, all spikes green)

scenes/main.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=19 format=3]
+[gd_scene load_steps=20 format=3]
 
 [ext_resource type="Script" path="res://scripts/Main.cs" id="1_main"]
 [ext_resource type="PackedScene" path="res://scenes/teleport_marker.tscn" id="2_marker"]
@@ -9,6 +9,7 @@
 [ext_resource type="Script" path="res://scripts/PropGrabber.cs" id="7_propgrabber"]
 [ext_resource type="Script" path="res://scripts/PhysicsHands.cs" id="8_physicshands"]
 [ext_resource type="Script" path="res://scripts/BodyRig.cs" id="9_bodyrig"]
+[ext_resource type="Script" path="res://scripts/PhysicsTorso.cs" id="10_physicsTorso"]
 
 [sub_resource type="ProceduralSkyMaterial" id="ProceduralSkyMaterial_sky"]
 sky_horizon_color = Color(0.66, 0.72, 0.81, 1)
@@ -55,6 +56,7 @@ shadow_bias = 0.04
 shadow_normal_bias = 0.5
 
 [node name="Floor" type="StaticBody3D" parent="."]
+collision_mask = 13
 
 [node name="FloorShape" type="CollisionShape3D" parent="Floor"]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, -0.05, 0)
@@ -113,6 +115,9 @@ script = ExtResource("7_propgrabber")
 [node name="PhysicsHands" type="Node" parent="."]
 script = ExtResource("8_physicshands")
 
+[node name="PhysicsTorso" type="Node" parent="."]
+script = ExtResource("10_physicsTorso")
+
 [node name="BodyRig" type="Node3D" parent="."]
 script = ExtResource("9_bodyrig")