chore(router): add appearance sub-routes

- Added theme route
- Added font route

Author: fulleni

lib/router/routes.dart

@@ -55,6 +55,13 @@ abstract final class Routes {
   // --- Settings Sub-Routes (relative to /account/settings) ---
   static const settingsAppearance = 'appearance';
   static const settingsAppearanceName = 'settingsAppearance';
+
+  // --- Appearance Sub-Routes (relative to /account/settings/appearance) ---
+  static const settingsAppearanceTheme = 'theme'; // Path: /account/settings/appearance/theme
+  static const settingsAppearanceThemeName = 'settingsAppearanceTheme';
+  static const settingsAppearanceFont = 'font'; // Path: /account/settings/appearance/font
+  static const settingsAppearanceFontName = 'settingsAppearanceFont';
+
   static const settingsFeed = 'feed';
   static const settingsFeedName = 'settingsFeed';
   static const settingsArticle = 'article';