Add alt text to img elements for accessibility

[ultraboy5522]

Resolves #190
audited and updated the alt attributes across all <img> tags on the page to make sure they follow proper accessibility (a11y/WCAG) standards:

• Country cards: Set alt="" on the images. Because the image and the text label (e.g., <span>Hong Kong</span>) live inside the same <a> tag, giving the image its own alt text caused screen readers to read the country name twice ("Hong Kong image Hong Kong link"). Marking the image as decorative lets the screen reader just announce just the link text.
• Logos & Icons: Added descriptive alt text for standalone graphics that sit outside text tags (like alt="Target logo" and alt="Upward trend icon").

Everything has been tested and works as intended.

[github-actions]

Thank you for opening a pull request @ultraboy5522. We will review it as soon as possible 🙌❤️

[ultraboy5522]

Hi @Virtual4087, hope you're doing well! Whenever you get a chance, would you mind taking a quick look at this accessibility fix? No rush at all. Thanks!