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>

package.json

@@ -24,7 +24,6 @@
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "@tailwindcss/vite": "^4.1.18",
     "@tanstack/react-devtools": "latest",
     "@tanstack/react-router": "latest",
     "@tanstack/react-router-devtools": "latest",
@@ -36,7 +35,6 @@
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
     "stripe": "^22.6.1",
-    "tailwindcss": "^4.1.18",
     "zod": "^4.5.4"
   },
   "devDependencies": {