chore: upgrade dependencies, restructure shared libs, and fix UI

- Upgrade Nx 22.1.1 → 22.6.3 and all patch/minor dependencies
- Restructure shared libs: move business logic from utils to service
- Consolidate shadcn-ui into ui lib with atomic design pattern
- Fix container centering for landing app (Tailwind v4 compatibility)
- Fix button styling by updating @source directive in globals.css
- Fix SiCss3 → SiCss rename in react-icons 5.6
- Fix duplicate useSession export conflict
- Remove dead code, comments, and unused files

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/hackathon/src/app/users/[userId]/layout.tsx

@@ -10,7 +10,7 @@ const UserDetailLayout: FC = (): ReactElement => {
       <Sidebar isOpen={sidebarOpen} onClose={() => setSidebarOpen(false)} />
 
       <div className="flex-1 flex flex-col overflow-auto">
-        {/* Mobile Header with Hamburger */}
+
         <div className="lg:hidden bg-white dark:bg-gray-900 border-b dark:border-neutral-700 px-4 py-3 flex items-center">
           <button
             onClick={() => setSidebarOpen(true)}