Add first-login password setup flow

Accounts created by tenant/store onboarding (createtenantuser,
createtenantlocation) have no password set. Previously the login form
treated the backend's "please setup a password" response as a
successful login instead of prompting for one. Now auth.ts recognizes
it (PasswordSetupRequiredError) and LoginView routes to a create-
password step, then signs in immediately with the new password.

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

src/services/fiestaQueries.ts

@@ -54,6 +54,7 @@ import {
   getUserById,
   createUser,
   updateUser,
+  setUserPassword,
   assignRiderToOrders,
   CreateUserInput,
   createTenantUser,
@@ -892,6 +893,18 @@ export function useLogin() {
   });
 }
 
+/**
+ * Set (or reset) a user's login password — used by the login flow's
+ * create-password step (see PasswordSetupRequiredError in ./auth) for a
+ * first-time tenant admin or store login.
+ */
+export function useSetPassword() {
+  return useMutation({
+    mutationFn: (input: { userid: number; password: string }) =>
+      setUserPassword(input.userid, input.password),
+  });
+}
+
 export function useFiestaDeleteLocation() {
   const qc = useQueryClient();
   return useMutation({