One file owns the court: beats.js, PROJECT.md (né HANDOFF), and tests gate the build

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

render.js

@@ -653,7 +653,7 @@ function drawZombie(zb) {
   // frame sliced 13 px shorter than its neighbours was being stretched back to full size — the body
   // grew and shrank once per stride. Oliver: "the brute is still pulsating while walking". The rule
   // already existed for the wound stages; it belongs to every frame, and it is the same rule
-  // _slice.py's common scaling is built on (see HANDOFF: heights follow the PNG).
+  // _slice.py's common scaling is built on (see PROJECT.md: heights follow the PNG).
   if (SPR[name]) h *= SPR[name].height / SPRITE_H;
   // feeding: a fast bob over the body instead of a stride. Same sprites, different rhythm.
   const bob = zb.feeding ? Math.abs(Math.sin(zb.walkT * 11)) * Math.max(1, p0(zb) * 0.05)