fix: add zoom-in duplicate class bug demo (fixes #872)

[Krish0703-irl]

Pull Request Description

This submission demonstrates the .ease-zoom-in duplicate class bug in core/animations.css
by showing both conflicting animations side-by-side, making it easy for the maintainer
to visually confirm the correct behavior before fixing it in core.

Related issue: #872

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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/ZoomIn-Duplicate-Fix/
• 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?
A side-by-side demo exposing the .ease-zoom-in duplicate class bug where two
different @keyframes blocks produce conflicting behavior and one is dead code.

How does a developer use it?

<div class="ease-zoom-in">I animate in correctly</div>

Why does it fit EaseMotion CSS?
EaseMotion CSS is animation-first and consistency is core to its philosophy.
Having two definitions of .ease-zoom-in referencing different keyframes breaks
that consistency — one animates from scale(0) with no opacity change, the other
from opacity:0, scale(0.85) using design tokens. The second definition silently
wins via CSS cascade, making the first dead code. This demo makes the case for
cleaning up the duplicate so the framework behaves predictably.

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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 PR is a companion to issue #872. The core fix requires:

1. Removing the first .ease-zoom-in block (~line 452) and orphaned @keyframes ease-zoom-in
2. Keeping the second definition using ease-kf-zoom-in with design tokens
3. Also cleaning up duplicate @keyframes ease-kf-slide-image-exit (lines 333, 372, 390),
   @keyframes ease-kf-shimmer-sweep (lines 343, 382) and .ease-shimmer-sweep class (lines 499, 516)
4. Regenerating easemotion.min.css via npm run build

Feel free to adjust timing or naming during integration.

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