Add flip border hover animation utility

[AnanyaTiwari850]

Pull Request Description

Added a new ease-flip-border-hover utility animation for smooth flip-style hover interactions on border components using pure CSS.

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Type of Change

• ✨ New animation / hover effect
• 🧩 New component
• 📝 Documentation improvement
• 🐛 Bug fix in an existing submission
• Other (describe below)

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Submission Checklist

⚠️ PRs that fail this checklist will be closed without review.

• All changes are inside submissions/examples/flip-border-hover/
• Includes demo.html — self-contained, opens in browser with no server
• Includes style.css — raw CSS for the proposed feature
• Includes README.md — what it does, how to use it, why it fits EaseMotion CSS
• No changes to core/
• No changes to components/
• One feature per PR (no bundled unrelated changes)

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Feature Description

What does this add?

This feature adds a smooth flip-style hover animation for border components.
The bordered component performs a subtle horizontal flip effect during hover interactions, creating a modern and interactive feel.

How does a developer use it?

<div class="ease-flip-border-hover">
  Hover Me
</div>

Why does it fit EaseMotion CSS?

• Lightweight pure CSS utility
• Smooth reusable hover interaction
• Modern visual feedback effect
• Beginner-friendly implementation
• Follows EaseMotion CSS naming conventions

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Demo

• Demo added (demo.html works by opening directly in a browser)

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Browser Testing

• Chrome
• Firefox
• Edge
• Safari (optional but appreciated)

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Notes for Maintainer

Closes #75

[github-actions]

✅ Submission Validation Passed!

Great job! All required files are present.

📁 Folder: submissions/examples/flip-border-hover

Files found:

• ✅ demo.html
• ✅ style.css
• ✅ README.md

🚀 Next Steps:

• The maintainer will review your PR
• Respond to any feedback if requested
• Once approved, your contribution will be merged!

Thank you for contributing to EaseMotion CSS! 🎉