Replace hardcoded header, footer and mobile nav with settings-driven
loops. Nav items stored as JSON via Settings, loaded in ThemeHook with
sensible defaults. New admin navigation editor at /admin/navigation
for add/remove/reorder/save/reset. Mobile bottom nav also driven from
header nav items with icon mapping by slug.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
