add the arbitrary-service pre-auth client factory

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/lib/lexClient.ts

@@ -24,3 +24,23 @@ export function createLexClient(
 ): Client {
   return new Client(agent, {strictResponseProcessing: false, ...options})
 }
+
+/**
+ * An unauthenticated {@link Client} pointed at an arbitrary service URL, for
+ * the PRE-AUTH flows that talk to a host the user typed or picked (hosting
+ * provider description, password reset, handle availability). Those requests
+ * cannot go through a session-scoped client, because there is no session yet.
+ *
+ * Deliberately NOT memoized: `service` is user-supplied and changes as the user
+ * edits it, so there is no stable key to cache on. Each call builds a fresh
+ * client, mirroring the ad-hoc agents these call sites constructed inline. That
+ * keeps client identity per-render, so callers must not put the returned client
+ * in a React Query key or a dependency array.
+ *
+ * Requests use PLAIN `fetch`, not `networkAwareFetch`: the host is untrusted
+ * input, and a typo'd or dead service must not be reported as the app losing
+ * network reachability.
+ */
+export function createServiceClient(service: string): Client {
+  return createLexClient({service})
+}