fix: descend undo notes and smooth next-level transitions

wechat-campaign-200-r2/qa/bright-classroom.html

@@ -32,7 +32,7 @@ function boot(){
  for(const n of ['TouchStart','TouchMove','TouchEnd','TouchCancel','Hide','Show','WindowResize'])wx['on'+n]=cb=>handlers[n]=cb;
  const global={};new Function('wx','GameGlobal','requestAnimationFrame','cancelAnimationFrame','setTimeout','clearTimeout','Date',source)(wx,global,fn=>{frames.set(++frame,fn);return frame;},id=>frames.delete(id),later,cancel,Clock);
  const api=global.numberSwipeR2,canvas=canvases[0];canvas.style.width=width+'px';canvas.style.height=height+'px';phone.style.width=width+'px';phone.replaceChildren(canvas);
- function tick(ms=16){now+=ms;const entry=frames.entries().next().value;if(entry){frames.delete(entry[0]);entry[1]();}}
+ function tick(ms=16){now+=ms;const callbacks=[...frames.values()];frames.clear();for(const fn of callbacks)fn();}
  function touch(kind,x,y){handlers[kind]({changedTouches:[{identifier:1,clientX:x,clientY:y}],touches:[{identifier:1,clientX:x,clientY:y}]});}
  function tap(x,y){touch('TouchStart',x,y);touch('TouchEnd',x,y);tick();}
  function button(name){const b=api.buttons().find(b=>b.label===name&&b.enabled);if(!b)throw Error('缺少按钮 '+name);tap(b.x+b.w/2,b.y+b.h/2);}