Multiple UI Fixes and Configuration Improvements

[JefferMarcelino]

This PR introduces several UI enhancements and a configuration update:

• Added .env file to .gitignore to prevent sensitive data from being committed.
• Improved navbar behavior by using URLs as unique keys, preventing duplicate key errors.
• Updated the footer to display a white logo for better visibility.
• Ensured the current year is dynamically shown on the footer.
• External URLs now open in a new tab for better user experience.

[vercel]

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