This PR make out-of-viewport but selected edgeless block keep active, since the selected block may still have some user interactions on the DOM. For example, when hover on a selected note and scroll viewport by wheel to view its hidden content, the note should not be hidden (a.k.a idel).
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## Summary by CodeRabbit
- **Refactor**
- Updated viewport logic to keep selected items visible instead of only those being edited. Visibility now depends on selection status rather than editing state.
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