Internationalization: Multi-language support

[biswajit-debnath]

Summary

Add internationalization (i18n) support to allow users to use IntelliJournal in multiple languages.

Details

• Implement a robust i18n framework for UI elements and messages.
• Provide language resource files (e.g., JSON, YAML, or PO files) for different languages.
• Ensure all visible strings are translatable.
• Set up language switching in the user interface.
• Use best practices for localization, including date, time, and number formatting.

Acceptance Criteria

• Users can select from at least two languages (e.g., English and one additional language).
• All UI text and messages change according to the selected language.
• The default language is English.
• Documentation updated to describe i18n setup and how to contribute translations.

Additional Notes

Consider using popular libraries/frameworks for internationalization depending on the technology stack (e.g., i18next for JavaScript).

[dikamjit-borah]

@biswajit-debnath please assign me to this issue. I have implemented internalization with i8n in my previous projects.

[biswajit-debnath]

Assigned @dikamjit-borah