feat: improve comparison video synchronization with frame callbacks

[Priyanshu1-62]

Description

• Replaced the throttled timeupdate-based synchronization mechanism with a frame-based synchronization loop using requestVideoFrameCallback(), with a fallback to requestAnimationFrame() for unsupported browsers.
• The synchronization loop is started on playback, cancelled on pause, end, and component unmount, resulting in smoother playback synchronization between the comparison videos.
• Prevented duplicate synchronization loops by ensuring only one active frame callback is scheduled at a time.

Related Issue

• Closes [FEATURE]: Improve dual video synchronization using frame-based updates #1672

Type of Contribution

• Bug fix
• New feature
• Documentation update
• Refactor
• GSSoC contribution

Participant Info

• GitHub username: Priyanshu1-62
• Contribution level: Intermediate (Some experience required)

Checklist

• I have read the contribution guidelines
• My changes follow the project structure
• I have tested my changes in Chrome, Firefox, and Safari
• bun run lint passes (no ESLint errors)
• bunx tsc --noEmit passes (no TypeScript errors)
• New interactive elements have aria-label / accessible names
• No console.log statements left in
• This PR is related to a valid issue
• Screen recording attached above

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[github-actions]

👋 Thanks for your PR, @Priyanshu1-62!

Welcome to Reframe — a browser-based video editor built for everyone 🎬

🟠 GSSoC'26 PR detected — thanks for contributing under GirlScript Summer of Code 2026!

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[github-actions]

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