feat: add multi-track timeline for video, audio, image and text clips…

[Bhavy12-cell]

Summary

Closes #1512

What's Added

New Files

• src/components/MultiTrackTimeline.tsx
  Full NLE-style multi-track timeline component with:

  • Layered video, audio, image, and text tracks
  • Draggable clip blocks with reposition support
  • Click-to-scrub ruler with playhead sync
  • Add track buttons per type
  • Delete clips per track
  • Track + clip count footer

• src/hooks/useMultiTrackTimeline.ts
  State management hook for timeline with:

  • addTrack(type) — adds new track of given type
  • addClip(trackId, clip) — places clip on a track
  • moveClip(clipId, trackId, newStart) — repositions clip
  • deleteClip(clipId, trackId) — removes clip

Modified Files

• src/components/VideoEditor.tsx
  Added MultiTrackTimeline section below the editing controls,
  visible when a file is loaded.

Architecture Notes

• Zero new dependencies — pure React state + CSS
• No FFmpeg.wasm changes — timeline is UI only
• Follows existing EditRecipe pattern and cn() utility
• Static export compatible — no server features used
• All hooks called before any conditional returns

Checklist

• ✅ Multiple video/audio/image/text tracks
• ✅ Draggable clip repositioning
• ✅ Click-to-scrub playhead on ruler
• ✅ Add/delete tracks and clips
• ✅ No new dependencies
• ✅ No TypeScript errors
• ✅ Static export compatible

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[github-actions]

👋 Thanks for your PR, @Bhavy12-cell!

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

What happens next

1. 🤖 Automated checks — build & TypeScript typecheck will run automatically
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4. 🚀 Merge — once approved, your PR will be merged!

Quick checklist

• PR title follows Conventional Commits (e.g. feat: add dark mode)
• Linked the issue this PR closes (e.g. Closes #123)
• Tested the changes locally (bun run dev)
• Build passes (bun run build)

Useful links

• 📖 CONTRIBUTING.md
• 🐛 Open Issues
• ⭐ Star the repo to support the project!

Happy coding! 🎉

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