Move MenuItem/MenuSection interfaces and the full menuSections array (6 sections,
~30 items with inline SVG icons) verbatim from Sidebar.tsx into src/admin/ui/navData.tsx.
Add exported isItemActive/hasItemPermission pure helpers (folding in the matchAlso
branch that was previously inline in Sidebar's NavLink className callback).
Sidebar updated to import and use these; rendering and active-state behavior unchanged.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
