add private to bookmark default open setting

apps/weblibre/lib/features/user/data/models/general_settings.dart

@@ -92,7 +92,7 @@ enum TabIntentOpenSetting { regular, private, isolated, ask }
 /// Determines what happens when a bookmark is tapped in the bookmark list.
 /// [ask] shows the "open in..." sheet (today's behavior, and the default);
 /// the other values open the bookmark directly with no intermediate prompt.
-enum BookmarkOpenSetting { regular, isolated, customTab, ask }
+enum BookmarkOpenSetting { regular, private, isolated, customTab, ask }
 
 enum TabDirection { newestFirst, oldestFirst }
 

apps/weblibre/lib/features/user/data/models/general_settings.g.dart

@@ -1352,6 +1352,7 @@ const _$TabIntentOpenSettingEnumMap = {
 
 const _$BookmarkOpenSettingEnumMap = {
   BookmarkOpenSetting.regular: 'regular',
+  BookmarkOpenSetting.private: 'private',
   BookmarkOpenSetting.isolated: 'isolated',
   BookmarkOpenSetting.customTab: 'customTab',
   BookmarkOpenSetting.ask: 'ask',