feat: add interactive dual-thumb timeline range slider with live video scrubbing

[SatyaViswas]

Description

This PR introduces an interactive, dual-thumb range slider overlay directly on top of the trimming timeline to drastically elevate the visual editing workflow.
Key changes include:

• Interactive Timeline Tracks: Implemented dual-thumb visual handles inside src/components/TrimControl.tsx overlaying the WaveformCanvas container. Powered by standard React pointer events (onPointerDown, onPointerMove, onPointerUp) to guarantee native desktop and touch-screen responsiveness.
• Live Video Scrubbing: Hooked the active dragging state into the parent seekTo context passed down via src/components/VideoEditor.tsx. The HTML5 video element now mirrors timeline adjustments frame-by-frame in real-time.
• URL Caching Optimization: Wrapped the query-parameter tracking mechanism within src/hooks/useVideoEditor.ts inside a 500ms debounce loop. This completely eliminates client-side SecurityError page crashes caused by rapid history.replaceState triggers during handle scrubbing.
• Accessibility Maintained: Retained full functionality of the native numeric inputs underneath the track for pixel-perfect millisecond precision and accessible screen-reader compatibility.

Related Issue

Fixes #537

Type of Contribution

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

Participant Info

• GitHub username: @SatyaViswas
• Contribution level (Beginner/Intermediate/Advanced): Intermediate/Advanced

Screen Recording

Before:

Screen.Recording.2026-05-21.at.7.30.34.PM.mov

After:

Screen.Recording.2026-05-21.at.7.28.16.PM.mov

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 (required for UI/feature/design changes)

[vercel]

@SatyaViswas is attempting to deploy a commit to the magic-peach1's projects Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

👋 Thanks for your PR, @SatyaViswas!

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

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

What happens next

1. 🤖 Automated checks — build & TypeScript typecheck will run automatically
2. ✅ Vercel preview — a preview deployment will be created (requires maintainer authorization for fork PRs)
3. 👀 Code review — a maintainer will review your changes
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! 🎉

[github-actions]

✅ PR Format Check Passed — @SatyaViswas

Basic format checks passed. A maintainer will review your code changes.

This does not mean the PR is approved — it just means the format is correct.

[magic-peach]

Hey @SatyaViswas! CI hasn't run on this PR yet. Please rebase on main to trigger the build/lint/typecheck checks:

git fetch origin
git rebase origin/main
git push --force-with-lease

Also, please attach a screen recording showing your change working in the browser (see CONTRIBUTING.md for instructions). Both CI and a recording are required before a PR can be merged.

[SatyaViswas]

Hey @magic-peach , I have resolved the conflicts on this branch! Also I attached the screen recording before already, but I am attaching again.

Screen.Recording.2026-05-21.at.7.28.16.PM.mov

[SatyaViswas]

Hey @magic-peach , just to remind, I resolved all conflicts and my PR is upto date with the main branch. Please review and merge my PR!

[SatyaViswas]

Hey @magic-peach. I resolved all the latest conflicts and my PR is upto date with the main branch. Please review and merge my PR!

[SatyaViswas]

Hey @magic-peach , could you please review this PR and close it, so that I could work on new issue!

I also solved the Application error shown in image which occurs when we use adjustment or trim options too many times:

[magic-peach]

@SatyaViswas This PR has merge conflicts with main and hasn't run the full CI suite yet (build, lint, and typecheck checks haven't run).

Please rebase your branch on main:

git fetch origin
git rebase origin/main
git push --force-with-lease origin feat/timeline-trim-slider

After rebasing, CI will run automatically. The interactive dual-thumb slider feature looks promising — once conflicts are resolved and CI passes, this will be reviewed for merge.

[SatyaViswas]

Hey @magic-peach , I have solved the conflicts. Please review and merge the PR!

[SatyaViswas]

Hey @magic-peach , I have resolved all conflicts in my PR. Please review and merge it!

[SatyaViswas]

Hey @magic-peach , I have also fixed the ffmpeg export error occurring in the main branch. Please review my PR!

[SatyaViswas]

Hey @magic-peach , you recently merged my PR #1199 , which fixed the ffmpeg export error. But I guess another PR merge by someone else made the ffmpeg export error return. But in this PR, the exporting still works without any error. I have also solved all CI build issues too.Please review and merge my PR!

[SatyaViswas]

Also this is the new UI change in trim section:

Screen.Recording.2026-05-27.at.10.20.06.AM.mov