Add i18n Support for Multi-Language Interface

[cadudotdev]

The WorkLog Chrome extension currently features a time calculation sheet with a user interface in Portuguese (e.g., "Hora", "Minutos", "Adicionar marcador", "Remover marcador"). This issue aims to implement internationalization (i18n) support to allow the interface to be translated into English and other languages, enhancing accessibility for a global audience. The implementation should utilize React, TypeScript, and TailwindCSS, ensuring compatibility with Chrome Extension Manifest V3.

Key Requirements:

• Integrate an i18n library (e.g., react-i18next or similar) to manage translations.
• Create translation files for at least English and Portuguese (e.g., en.json, pt.json) to cover the current UI elements (e.g., labels, buttons, total time display).
• Update the time calculation sheet screen to dynamically switch languages based on user preference or browser settings.
• Ensure TailwindCSS styles adapt to translated text lengths (e.g., flexible button widths).
• Provide a simple method for users to select their preferred language (e.g., a dropdown or settings option).
• Test the interface in multiple languages to verify layout and functionality.
• Document the i18n setup in the README or a dedicated i18n.md file for contributors.

Current State:

• The main screen displays text in Portuguese, including "Hora", "Minutos", "Adicionar marcador", "Remover marcador", and "Tempo ocupado" with values (e.g., 9h 0m, 9.00h).