Entropy, contact queue, secondary trigger, physics fixes
- Add ContactQueue for thread-safe physics contact event buffering
- Process contact events on main thread in Scene::tick
- Add Entropy: spherical physics body attracted to player
- Entropy spawns with random velocity and homes toward player
- Entropy removes itself on contact with player
- Add Entropy destructor to clean up physics body on removal
- Cache BodyInterface reference in Entropy to use in destructor
- Add Player::secondaryTrig spawning a ring of 60 Entropy orbs
- Bind secondary trigger to right mouse button in gameplay
- Add bodySettings restitution and initial velocity to Entropy
- Remove Entropy from hardcoded gameplay.json scene
- Fix Entropy tick to apply yaw-only rotation from physics body
- Add bug note: crash on unassigned material slots