Add accessible dialog pattern to MenuItemModal

[mighty840]

Description

The storefront MenuItemModal is missing standard accessible dialog attributes. It currently has no role="dialog", no aria-modal="true", and no aria-labelledby pointing to the item's heading.

Files to Change

• packages/storefront/src/components/MenuItemModal.tsx — lines 152–158

Requirements

1. Add role="dialog" to the modal container
2. Add aria-modal="true"
3. Add aria-labelledby pointing to the item name heading's id
4. Ensure focus is trapped within the modal when open
5. Ensure pressing Escape closes the modal

Reference

See WAI-ARIA Dialog Pattern

Effort

S — focused accessibility improvement