Bring the codebase in line with CLAUDE.md conventions

- Convert getRouter, OrderingPage, and OrderStatusRoute from function
  declarations to arrow functions
- Migrate header-user.tsx off raw Tailwind classes onto a co-located
  SCSS module, and remove Tailwind entirely (deps, Vite plugin,
  styles.css) since it was the only consumer and duplicated the
  documented SCSS Modules system
- Fix CLAUDE.md's stale ~/ alias example and structure diagram to
  match the project's actual #/ and @/ aliases and directories

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/routes/__root.tsx

@@ -2,7 +2,6 @@ import { HeadContent, Scripts, createRootRoute } from '@tanstack/react-router'
 import { TanStackRouterDevtoolsPanel } from '@tanstack/react-router-devtools'
 import { TanStackDevtools } from '@tanstack/react-devtools'
 
-import appCss from '../styles.css?url'
 import '../styles/globals.scss'
 
 const RootDocument = ({ children }: { children: React.ReactNode }) => (
@@ -42,12 +41,6 @@ export const Route = createRootRoute({
         title: 'Ghost Kitchen',
       },
     ],
-    links: [
-      {
-        rel: 'stylesheet',
-        href: appCss,
-      },
-    ],
   }),
   shellComponent: RootDocument,
 })