track时间轴错乱

最近发现首次用软件打开草稿好好的，什么都不动，关闭后再打开，会自动生成新的track，有些segment会被自动加载到新的track上，（p.s.：最近导出的视频有视频和音频音画不同步才发现上面的现象的，capcut和剪映专业版都有一样现象）

Start by reproducing the reported behavior with a CapCut draft: open it, close it without changes, reopen it, and inspect whether new tracks and moved segments appear. Compare the resulting track layout with the exported audio and video synchronization; done means reopening no longer changes track assignment or causes desynchronization.

Written by the indexing model from the issue text.