The cockpit rail had 6 text-only items whose scrollToAnchor targeted
non-existent IDs (clicks did nothing) and diverged from the reference.
Replace with the prototype's 7 icon+label items (Участок/Потенциал/Продукт/
Экономика/Риски/Сравнение/Отчёты, icons ported from the kit). Discriminated
union RailItem {kind:'scroll'|'tab'}: scroll items activate the analysis tab
then scrollIntoView the matching section on the next frame; tab items switch
the top tab. Add ptica-hero/-potential/-product/-economy/-risks section IDs;
port the .nav-item active state (cyan accent + glow + left bar).
