Give the paging loop, Link-header parser and FieldConfig one home each, rename buildPluginChrome to buildPageChrome, and delete a group from its parents

src/auth/link-header.ts

@@ -0,0 +1,7 @@
+// Kratos and Hydra both paginate with an RFC 8288 `Link` header. Returns the `page_token` of its
+// `rel="next"` entry, or null on the last page. The href is a relative path, so it is resolved
+// against a throwaway base just to read the query parameter.
+export function nextPageToken(link: string | null): string | null {
+  const href = link?.match(/<([^>]+)>\s*;\s*rel="next"/)?.[1];
+  return href ? new URL(href, "http://link-header.invalid").searchParams.get("page_token") : null;
+}