Refactor notification service and enhance user management features

- Replaced legacy payment notification functions with a new NotificationService for improved code organization and maintainability.
- Updated user management handlers to utilize the new notification system for payment confirmations.
- Enhanced user card formatting with localized labels for better clarity and user experience.
- Introduced context management for the PanelApiService to ensure proper session handling.
- Updated localization files to include new labels and messages for user management and notifications.

bot/handlers/user/start.py

@@ -237,7 +237,6 @@ async def start_command_handler(message: types.Message,
                 config_link = active.get("config_link") if active else None
                 config_link = config_link or _("config_link_not_available")
                 
-                from datetime import datetime
                 new_end_date = result if isinstance(result, datetime) else None
                 
                 promo_success_text = _(