Show the backend's Persian error (errors[0].message, e.g. rate-limit
'درخواستهای زیاد') as a toast for any failed request.* call, from the
axios response interceptor — so failures are no longer silent. 401 still
logs out/redirects without a toast; callers can opt out with
config.skipErrorToast. Drop now-redundant per-caller alerts/toasts in
the booking submit, payment, and OTP userinfo paths.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>