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>

CLAUDE.md

@@ -38,8 +38,13 @@ src/
 ├── routeTree.gen.ts    # AUTO-GENERATED — never edit by hand
 ├── router.tsx           # router instance/config
 ├── components/
-│   ├── ui/               # base primitives (buttons, inputs, etc.)
-│   └── <domain>/         # feature-specific components, e.g. posts/, auth/
+│   ├── ui/               # base primitives (buttons, inputs, etc.) — not
+│   │                       populated yet; add it when a shared primitive
+│   │                       is needed
+│   └── <domain>/         # feature-specific components, e.g. ordering/, orders/
+├── domain/                # framework-free business logic, e.g. ordering.ts
+├── server/                # server functions (createServerFn) callable from routes
+├── integrations/          # third-party integration glue, e.g. better-auth/
 ├── lib/                  # shared utilities, API clients, helpers
 ├── db/
 │   ├── schema.ts         # Drizzle schema definitions
@@ -73,7 +78,8 @@ drizzle/                  # generated SQL migrations — never hand-edit
 - Class names in `.module.scss` files are camelCase (e.g. `.cardHeader`, not
   `.card-header`) so they read naturally as `styles.cardHeader`.
 - Shared tokens (colors, spacing, breakpoints) live in `src/styles/_variables.scss`
-  and are pulled in with `@use '~/styles/variables' as *;` — don't hardcode
+  and are pulled in with a relative `@use '../styles/variables' as *;` (Sass
+  doesn't resolve the `#/`/`@/` TS path aliases) — don't hardcode
   colors/spacing that already exist as a variable.
 - `src/styles/globals.scss` is for resets and truly global rules only
   (imported once in `__root.tsx`); component-specific styles always go in a
@@ -94,7 +100,10 @@ drizzle/                  # generated SQL migrations — never hand-edit
   the `function` keyword — e.g. `const getUser = async (id: string) => {...}`
   and `export const Button = (props: ButtonProps) => {...}`.
 - [Naming conventions: PascalCase components, camelCase functions/vars, etc.]
-- [Import order / path aliases, e.g. `~/` or `@/` for `src/`]
+- Path aliases `#/*` and `@/*` both resolve to `src/*` (see `tsconfig.json`
+  and `package.json`'s `imports` field) — use either for TS/TSX imports.
+  SCSS files can't use these aliases; use relative `@use`/`@import` paths
+  there instead.
 - Co-locate a component's test file next to it unless it's a shared
   primitive in `components/ui/` (see "Styling" for `.module.scss` placement).
 - No comments unless they're unavoidable for understanding — e.g. explaining