Render menu page with useEffect + useState

## Goal
Render a menu page that fetches foods inside `useEffect`, manages `loading` / `error` / `data` state with `useState`, and displays cards in a responsive grid. This is the naive-fetching baseline before introducing TanStack Query — students should feel the boilerplate first.

## Acceptance criteria
- [ ] `/menu` route fetches foods on mount with `useEffect`
- [ ] Loading state shows the `Spinner`
- [ ] Error state shows a clear message
- [ ] Foods render as a responsive grid of `FoodCard`s
- [ ] Playwright test verifies the menu loads and renders multiple cards