feat: add appear on scroll animation submission

[AyushPrad2907]

Pull Request Description

This PR adds a new animation submission called Appear On Scroll Animation inside submissions/examples/appear-on-scroll/.

The submission demonstrates a CSS-first reveal effect where elements fade and slide into view, creating a smooth content discovery experience commonly used in modern landing pages and portfolios.

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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

• All changes are inside submissions/examples/appear-on-scroll/
• Includes demo.html
• Includes style.css
• Includes README.md
• No changes to core/
• No changes to components/
• One feature per PR

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Feature Description

What does this add?

A CSS-first reveal animation that fades and lifts content into view, simulating a modern scroll-reveal experience.

How does a developer use it?

<div class="scroll-reveal">
  Content appears with animation
</div>

Why does it fit EaseMotion CSS?

The effect is easy to understand, visually appealing, and commonly used across modern websites. It aligns with EaseMotion CSS's animation-first philosophy while remaining lightweight and reusable.

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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

This submission focuses on a CSS-first approach to reveal animations. Since true viewport detection is outside the scope of pure CSS in many browser environments, the demo showcases reusable reveal patterns and staggered animations that could serve as a foundation for future framework integration.

[github-actions]

✅ Submission Validation Passed!

Great job! All required files are present.

📁 Folder: submissions/examples/appear-on-scroll

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! 🎉