Refactor notification handling and streamline router registration

- Replaced legacy notification functions with a unified NotificationService for better maintainability and clarity.
- Updated the main bot router registration to utilize a root router, simplifying the inclusion of user and admin routes.
- Removed unused middleware and helper functions to enhance code cleanliness and focus on essential components.
- Improved localization by adding new error messages for user interactions.

locales/en.json

@@ -16,6 +16,7 @@
   "choose_language": "Choose language / Выберите язык:",
   "language_set_alert": "Language changed!",
   "error_occurred_try_again": "An error occurred, please try again.",
+  "error_try_again": "Please try again.",
   "error_displaying_menu": "Error displaying menu.",
   "main_menu_unknown_action": "Unknown action.",
 

locales/ru.json

@@ -16,6 +16,7 @@
   "choose_language": "Выберите язык / Select language:",
   "language_set_alert": "Язык изменен!",
   "error_occurred_try_again": "Произошла ошибка, попробуйте снова.",
+  "error_try_again": "Попробуйте еще раз.",
   "error_displaying_menu": "Ошибка отображения меню.",
   "main_menu_unknown_action": "Неизвестное действие.",