Default API to M5Max48:3002; preserve portal_config on session expiry

src/api/client.ts

@@ -127,7 +127,6 @@ function isTauri(): boolean {
 function handleSessionExpired() {
   console.warn("Session expired or connection error, redirecting to login...");
   localStorage.removeItem('momentry_user');
-  localStorage.removeItem('portal_config');
   localStorage.removeItem('momentry_api_key');
   if (window.location.pathname !== '/login') {
     window.location.href = '/login';