feat: ucp virtual route redirects to online store

[fredericoo]

WHY are these changes introduced?

Discussion: https://shopify.slack.com/archives/C049WL5S2L9/p1770138723859259

WHAT is this pull request doing?

• adds a new virtual route .well-known/ucp to @shopify/hydrogen
• adds a util normalizeUrl to account for differently entered urls in the PUBLIC_STORE_DOMAIN env var
• the route handler simply 301s to the online store domain. Proxying the request will not work unless we set up cloudflare custom hostnames too in oxygen deployments

HOW to test your changes?

• run store
• head to `http://localhost:3000/.well-known/ucp
• you should be redirected to a page with the json for ucp

Checklist

• I've read the Contributing Guidelines
• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've added a changeset if this PR contains user-facing or noteworthy changes
• I've added tests to cover my changes
• I've added or updated the documentation

[frandiox]

If it's a standard route, have we considered adding it directly to createRequestHandler (like our SFAPI proxy) instead of having it in the template route? cc @kdaviduik

[kdaviduik]

@frandiox @fredericoo yeah I think adding it inside createRequestHandler would be best. I'd also like to add in the storefront MCP support too, which would be done the same way

[fredericoo]

If it's a standard route, have we considered adding it directly to createRequestHandler (like our SFAPI proxy) instead of having it in the template route? cc @kdaviduik

our SFAPI proxy is api.$version.[graphql.json].tsx in routes, no?

EDIT: i’ve checked it out and it seems we do both!