Add i18n translation support for prompt messages and project documentation

[scarletkc]

Feature Request: Internationalization (i18n) Support

Description

We need to implement internationalization (i18n) support for the telegram summary bot to make it accessible to users who speak different languages. This feature should cover:

1. Prompt messages and user-facing text

   • Bot responses and notifications
   • Error messages
   • Help text and instructions
   • UI elements and buttons

2. Project documentation

   • README files
   • User guides
   • API documentation
   • Configuration instructions

Proposed Implementation

• Set up an i18n framework (e.g., i18next, react-i18next, or similar)
• Extract all hardcoded strings into translation files
• Create language files for different locales (starting with common languages)
• Update documentation to be available in multiple languages
• Add language detection and switching functionality

Benefits

• Makes the bot accessible to a wider international audience
• Improves user experience for non-English speakers
• Follows best practices for internationalization

Acceptance Criteria

• i18n framework is properly configured
• All user-facing strings are externalized to translation files
• At least 2-3 language translations are implemented
• Documentation is available in multiple languages
• Language switching mechanism is implemented
• Fallback to default language when translation is missing

This would be a great contribution for new contributors to get familiar with the codebase!