Physics stage 1a runs on Rapier: a new Rigidbody child object (body type, mass, gravity scale, damping, fixed rotation, CCD) makes its parent fall, bounce and come to rest in play, colliders gain friction, bounciness and density, the scene gains gravity (0, 980), the new PhysicsSystem steps at a fixed 60 Hz with interpolation in world coordinates and treats a tilemap as static ground, On collision enter gains normal and impulse, play waits for Rapier and does not start without it, and the editor run keeps the old CollisionSystem; the existing collision tests run against both systems unchanged (#146)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tools/e2e/lib/scaffold.mjs

@@ -21,6 +21,7 @@ export const LANES = {
   particles: -2300,
   sound: -2700,
   tilemap: -3100,
+  physics: -3500,
 };
 
 /**