feat: add slide button entrance animation submission

[Shreeya1207]

Description

This PR adds a new submission demonstrating a Slide Button Entrance animation effect.

Added Effect

• slide-button-entrance

Files Added

• submissions/examples/ease-slide-button-entrance/demo.html
• submissions/examples/ease-slide-button-entrance/style.css
• submissions/examples/ease-slide-button-entrance/README.md

Demo

The demo showcases a button that smoothly slides into view from the side while fading in. The animation creates an engaging entrance effect that helps highlight important call-to-action elements and interactive controls.

Why

Slide entrance animations improve visual hierarchy and help draw user attention to important actions. They are commonly used for call-to-action buttons, onboarding flows, landing pages, promotional sections, and interactive interfaces. This utility is lightweight, reusable, and aligns with EaseMotion CSS's philosophy of expressive and human-readable animation utilities.

Checklist

• Added files only inside submissions/
• Included demo.html
• Included style.css
• Included README.md
• One feature per PR
• Demo works without external dependencies
• Followed contribution guidelines

[github-actions]

✅ Submission Validation Passed!

Great job! All required files are present.

📁 Folder: submissions/examples/ease-slide-button-entrance

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! 🎉