6c4b076c68
WIND directive in .lvl files sets a constant horizontal force (px/s^2) that pushes entities, projectiles, and particles. Positive is rightward. Wind is applied as acceleration in physics_update() (halved on ground), directly to projectile and particle velocities, and as a gentle position drift on flyers. Entities with gravity_scale=0 (drones, spacecraft) are unaffected. Levels default to no wind when the directive is absent.