fix and update

apps/frontend/lib/api.ts

@@ -7,16 +7,25 @@ function resolveBrowserApiBaseUrl(): string {
     return configuredApiUrl;
   }
 
-  try {
-    const configured = new URL(configuredApiUrl);
-    if (configured.hostname !== window.location.hostname) {
-      return API_ORIGIN_PROXY_PREFIX;
-    }
-  } catch {
-    // keep configured URL
+  if (configuredApiUrl.startsWith('/')) {
+    return configuredApiUrl.replace(/\/+$/, '') || API_ORIGIN_PROXY_PREFIX;
   }
 
-  return configuredApiUrl;
+  try {
+    const configured = new URL(configuredApiUrl);
+    const sameHost =
+      configured.hostname === window.location.hostname &&
+      (configured.port || (configured.protocol === 'https:' ? '443' : '80')) ===
+        (window.location.port || (window.location.protocol === 'https:' ? '443' : '80'));
+
+    if (sameHost) {
+      return API_ORIGIN_PROXY_PREFIX;
+    }
+
+    return configuredApiUrl.replace(/\/+$/, '');
+  } catch {
+    return API_ORIGIN_PROXY_PREFIX;
+  }
 }
 
 function resolveBrowserWsBaseUrl(): string {

apps/frontend/lib/system-settings-catalog.ts

@@ -31,7 +31,7 @@ export const SYSTEM_SETTING_CATALOG: SystemSettingMeta[] = [
     label: 'URL API (OAuth issuer)',
     group: 'general',
     type: 'text',
-    hint: 'Базовый URL API для OAuth/OIDC и FedCM. При same-origin деплое: https://ваш-домен/idp-api'
+    hint: 'Публичный URL, доступный из браузера пользователя. Не используйте api-gateway или другие Docker-имена. Пример: https://id.lendry.ru/idp-api'
   },
   {
     key: 'PUBLIC_FRONTEND_URL',