Missing page: Shopping Cart (/cart)

Problem

The /cart route is not implemented in the application. When users try to navigate to /cart, they see an empty page with a console warning: "No routes matched location '/cart'"

Expected Behavior

• Users should be able to view items they've added to their shopping cart
• The cart page should display product details (name, image, price, quantity)
• Users should be able to update quantities or remove items
• Show total price calculation
• Provide a button to proceed to checkout

Current Behavior

• Navigation to /cart shows an empty page
• Console warning: "No routes matched location '/cart'"
• Footer links to "My Cart" use placeholder "#" href

Acceptance Criteria

• Create /cart route in React Router
• Implement Cart component with product list
• Show cart item count badge in navigation
• Allow quantity updates and item removal
• Display subtotal and total
• Add "Continue Shopping" and "Proceed to Checkout" buttons
• Handle empty cart state with friendly message
• Update navigation/footer links to point to /cart

Priority

High - This is a core e-commerce feature

Start by locating the React Router route definitions and the existing navigation and footer links that reference the cart. Trace how cart items and checkout navigation are currently represented before adding the /cart flow. Done means the route renders item details, quantity and removal controls, totals, navigation count, empty-cart handling, and the requested shopping and checkout links.