fix(userfront): restore web auth redirect variables after merge regression

userfront/lib/core/services/web_auth_integration_web.dart

@@ -3,16 +3,32 @@
 import 'dart:async';
 import 'dart:html' as html;
 import 'package:flutter/foundation.dart';
+import 'auth_token_store.dart';
 
 void implSendLoginSuccess(String token) {
-  final message = {'type': 'LOGIN_SUCCESS', 'token': token};
-  
-  if (html.window.opener != null) {
-    try {
-      html.window.opener!.postMessage(message, '*');
-      debugPrint('Sent login success message to opener');
-    } catch (e) {
-      debugPrint('Failed to postMessage: $e');
+  var effectiveToken = token;
+  if (effectiveToken.isEmpty) {
+    effectiveToken = AuthTokenStore.getToken() ?? "";
+  }
+
+  final fullUrl = html.window.location.href;
+  final uri = Uri.base;
+
+  // Try to find redirect_uri from standard parsing first, then manual string search
+  String? redirectUri =
+      uri.queryParameters['redirect_uri'] ??
+      uri.queryParameters['redirect_url'];
+
+  if (redirectUri == null) {
+    // Manual fallback for cases where Uri.base misses params
+    final searchParams = html.window.location.search;
+    if (searchParams != null && searchParams.isNotEmpty) {
+      final sUri = Uri.parse(
+        '?${searchParams.startsWith('?') ? searchParams.substring(1) : searchParams}',
+      );
+      redirectUri =
+          sUri.queryParameters['redirect_uri'] ??
+          sUri.queryParameters['redirect_url'];
     }
   }
 
@@ -63,9 +79,7 @@ void implSendLoginSuccess(String token) {
         debugPrint('Failed to close window: $e');
       }
     });
-  } else {
-     // Should not happen given isPopup check, but as fallback:
-    debugPrint('No opener found during popup flow.');
+    return;
   }
 
   // No opener and no redirect: fall back to local navigation