added support for multiple accounts, guardian login bugfixes, ui changes

lib/api/marianumconnect/auth/auth_interceptor.dart

@@ -20,6 +20,15 @@ class MarianumConnectAuthInterceptor extends Interceptor {
   // each spawning a fresh row in api_tokens.
   Future<bool>? _pendingReLogin;
 
+  static Future<bool>? _anyPendingReLogin;
+
+  /// Resolves once no silent re-login is running. An account switch waits for
+  /// it — the renewed token would otherwise land in the next account's slot.
+  static Future<void> idle() async {
+    final pending = _anyPendingReLogin;
+    if (pending != null) await pending;
+  }
+
   MarianumConnectAuthInterceptor({
     MarianumConnectTokenStorage tokenStorage =
         const MarianumConnectTokenStorage(),
@@ -85,8 +94,10 @@ class MarianumConnectAuthInterceptor extends Interceptor {
     if (inFlight != null) return inFlight;
     final fresh = _performReLogin();
     _pendingReLogin = fresh;
+    _anyPendingReLogin = fresh;
     fresh.whenComplete(() {
       if (identical(_pendingReLogin, fresh)) _pendingReLogin = null;
+      if (identical(_anyPendingReLogin, fresh)) _anyPendingReLogin = null;
     });
     return fresh;
   }