Errors look the same everywhere, with a request ID to quote

An unknown address or a failed sign-in callback now shows a page in Zitadel's design with a request ID, and the console's error screens share its layout. Programs get JSON: 404 req.not_found, or 405 req.method_not_allowed with Allow.

• The console's error screens show the failed request's ID instead of the error code, so a support request can quote it, and ApiError from @zitadel/api carries it as requestId.
• A not-found screen in the console names what is missing, such as "User not found", and leads back to its list.
• server.request_id_header takes the request ID from a proxy's header, such as x-vercel-id; set it only behind a proxy that overwrites it.