Add viewports to all three columns with cursor sync scrolling. Support
Shift+Tab reverse pane focus. Replace flat menu with hierarchical NavTree
(list loads only on leaf nodes; dynamic project subnodes with Tasks/Files).
Enter or a opens per-item action menu (view, delete, download) wired to
the OnlyOffice API.
Co-authored-by: Cursor <cursoragent@cursor.com>
