* fix: support bidirectional shift+click selection in library items
- Enable bottom-up multi-selection (previously only top-down worked)
- Use Math.min/max to handle selection range in both directions
- Maintains existing behavior for preserving non-contiguous selections
- Fixes issue where shift+clicking items above last selected item failed
* improve deselection behavior
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Co-authored-by: dwelle <5153846+dwelle@users.noreply.github.com>
