Add an "API Docs" navigation entry that opens /api/docs in a new tab.
It is shown only in the wide-mode navigation rail (not the compact
bottom bar) and sits just before About.
Generalises the navigation destination model so an entry can be an
in-app route or an external link, and can be restricted to wide layouts.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Let users collapse the wide-mode NavigationRail to an icons-only compact
view to reclaim horizontal space. A bottom-pinned double-chevron toggle
sits centred when compact and slides to the rail's right side when
extended, animating in sync with the rail. The choice is persisted via
the nav_rail_extended preference (defaults to extended).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
