feat(puppet): render-path uses cascaded world.scl + world.rot

Previously the render path read per-bone constant `b.scale` and
`ws.angle`. With multi-channel keyframes + scale-cascade, the rendered
sprite-scale comes from the cascaded `world.scl_x/y` and angle from
`world.rot`. No new tests — visual verification at Phase-4 manual test.

init.lua

@@ -2,6 +2,7 @@
 -- Skeletal animation: skeleton + bones + tracks + rest + keyframe
 -- + procedural + look-at constraint. Multi-channel animation (rot/pos/scl)
 -- + cascaded world-transform with scale propagation.
+-- Render path: world.scl_x/y (cascaded) + world.rot used for draw_sprite_transform.
 
 local M = {}