Add the customer ordering page

Builds the main customer-facing flow: browse the Brand's menu, add
items to a cart, and check out either as a guest (name + contact) or,
if signed in, as the account customer — both call the existing
placeOrder server function, which already distinguishes the two. On
success, navigates to a new /orders/$orderId status page showing each
Order Item's Preparation Steps, queue position, ETA, and (per the
domain rules already established) a Cancel button while cancellable
and a pickup-confirmation button once ready.

Styled with SCSS Modules per CLAUDE.md; added the sass dependency and
the src/styles/ structure it describes (globals.scss imported once in
__root.tsx, alongside the existing Tailwind stylesheet the not-yet-
mounted header-user.tsx component depends on).

Verified end-to-end against a throwaway local Postgres: menu renders
with seeded items, cart quantities update, guest checkout places a
real order, and the status page reflects a real cancellation.

Also fixes CLAUDE.md's Commands section, which documented pnpm even
though this repo only has npm (package-lock.json, no pnpm installed).

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

CLAUDE.md

@@ -12,17 +12,17 @@ Guidance for Claude Code when working in this repository.
 - Vite
 - SCSS Modules
 - Drizzle ORM + PostgreSQL
-- [Auth: Better Auth / Clerk / custom / none yet]
-- [Package manager: pnpm / npm / bun]
+- Better Auth
+- npm
 
 ## Commands
 
 ```bash
-pnpm dev          # start dev server (http://localhost:3000)
-pnpm build        # production build
-pnpm typecheck    # tsc --noEmit
-pnpm lint         # eslint
-pnpm test         # [test runner, e.g. vitest]
+npm run dev          # start dev server (http://localhost:3000)
+npm run build        # production build
+npm run typecheck    # tsc --noEmit
+npm run lint         # eslint
+npm test             # vitest run
 ```
 
 Always run `typecheck` and `lint` before considering a task done. If `build`