feat: Add animation playback control utility classes (#1119)

[Sweksha-Kakkar]

Changes Made

Closes #1119

Problem:

The library lacked utility classes to control animation playback state dynamically (pause, resume, infinite loop).

What's changed in core/utilities.css:

Added a new "Animation Playback Control" section with these utility classes:

• .motion-infinite — Sets animation-iteration-count: infinite
• .motion-pause — Sets animation-play-state: paused
• .motion-running — Sets animation-play-state: running
• .hover-pause:hover — Pauses animation on hover
• .hover-resume:hover — Resumes animation on hover
• .focus-pause:focus — Pauses animation on focus (accessibility)
• @media (prefers-reduced-motion) — Respects user's reduced motion preference

Usage Example:

<!-- Infinite loop -->
<div class="ease-fade-in motion-infinite">...</div>

<!-- Pause on hover -->
<div class="ease-bounce hover-pause">...</div>

<!-- Resume on hover -->
<div class="ease-pulse motion-pause hover-resume">...</div>

Checklist

• I have read the CONTRIBUTING.md
• My code follows the style guidelines of this project
• I have tested my changes locally
• This PR is linked to an issue
• I have added a proper description of my changes

[github-actions]

📊 CSS Bundle Size Benchmark

This PR changes the size of easemotion.min.css.

Metric	Base Branch	This PR	Difference
Raw	39.16 KB	39.57 KB	📈 +0.40 KB
Gzip	7.16 KB	7.24 KB	📈 +0.08 KB
Brotli	6.19 KB	6.27 KB	📈 +0.08 KB

[Sweksha-Kakkar]

@SAPTARSHI-coder
Please look into this and merge it.