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>

package.json

@@ -51,6 +51,7 @@
     "dotenv": "^17.3.1",
     "eslint": "^9.20.0",
     "prettier": "^3.8.1",
+    "sass": "^1.104.0",
     "tsx": "^4.21.0",
     "typescript": "^6.0.2",
     "vite": "^8.0.0",
@@ -62,4 +63,4 @@
       "lightningcss"
     ]
   }
-}
+}