feat: add baby object match edutainment flow

src/components/child-motion-demo/childMotionWarmupModel.ts

@@ -10,8 +10,7 @@ export type ChildMotionWarmupStepId =
   | 'wave_right_hand'
   | 'jump_once'
   | 'warmup_finish'
-  | 'level_select'
-  | 'play_placeholder';
+  | 'level_select';
 
 export type ChildMotionWarmupTarget = 'center' | 'left' | 'right';
 
@@ -20,8 +19,7 @@ export type ChildMotionWarmupStepKind =
   | 'gesture'
   | 'narration'
   | 'finish'
-  | 'levelSelect'
-  | 'placeholder';
+  | 'levelSelect';
 
 export type ChildMotionWarmupStep = {
   id: ChildMotionWarmupStepId;
@@ -151,12 +149,6 @@ export const CHILD_MOTION_WARMUP_STEPS: ChildMotionWarmupStep[] = [
     title: '准备开始',
     spokenLines: ['现在开始我们的游戏吧'],
   },
-  {
-    id: 'play_placeholder',
-    kind: 'placeholder',
-    title: '下一关',
-    spokenLines: ['游戏关卡正在准备中'],
-  },
 ];
 
 const STEP_BY_ID = new Map(