convert express example to use vite

[michenly]

Part of https://github.com/Shopify/hydrogen-internal/issues/109

Took a lot of setup from https://github.com/kiliman/remix-vite-template/tree/main as inspiration

[shopify]

Oxygen deployed a preview of your mc-express-example branch. Details:

Storefront	Status	Preview link	Deployment details	Last update (UTC)
Skeleton (skeleton.hydrogen.shop)	✅ Successful (Logs)	Preview deployment	Inspect deployment	June 11, 202411:57 AM
vite	✅ Successful (Logs)	Preview deployment	Inspect deployment	June 11, 202411:57 AM
subscriptions	✅ Successful (Logs)	Preview deployment	Inspect deployment	June 11, 202411:57 AM
third-party-queries-caching	✅ Successful (Logs)	Preview deployment	Inspect deployment	June 11, 202411:57 AM
optimistic-cart-ui	✅ Successful (Logs)	Preview deployment	Inspect deployment	June 11, 202411:57 AM
custom-cart-method	✅ Successful (Logs)	Preview deployment	Inspect deployment	June 11, 202411:57 AM

Learn more about Hydrogen's GitHub integration.

[frandiox]

Thanks! Requesting a few changing below.

Also, I noticed the following is not correct in Express:

requestGroupId: req.get('request-id'),
buyerIp: req.get('oxygen-buyer-ip'),

We should be using a random ID for the requestGroupId (generated in this file per request) and getting the user IP from the Express req object (something like req.headers['x-forwarded-for'] || req.socket.remoteAddress ).