Navbar now applies a mobileNavOpen style when the mobile menu is open, improving mobile compatibility. User area elements are moved into the link group for better mobile layout, and several CSS adjustments were made for smoother transitions and consistent icon sizing.
Replaces HomeNav with a new SiteNav and associated CSS module, updating navigation structure and user menu. Removes legacy API client, downloader, user model, and UserContext in favor of a new AuthContext stub for future authentication logic. Also cleans up HeroCarousel and minor CSS fixes.
