feat: add export history panel with re-download support

[imuniqueshiv]

Description

Implemented an export history panel that allows users to re-download previous exports during the current browser session.

Changes made

• Added in-memory exportHistory state inside useVideoEditor.ts

• Added support for storing up to 5 previous exports

• Created a new ExportHistory.tsx component

• Added a collapsible "Recent Exports" panel below the export result section

• Added metadata display for:

  • filename
  • format
  • file size
  • output dimensions
  • export timestamp

• Added "Download" button to re-trigger downloads using stored blob URLs

• Added "Clear History" button

• Implemented proper blob URL cleanup when:

  • history entries are evicted
  • history is cleared

• Added session-only history notice:

  • "History is cleared when you close or refresh the page"

• Updated UI styling to match the existing Reframe design system

Testing

• Verified old exports remain downloadable after exporting new videos
• Verified history is limited to 5 entries
• Verified oldest export is removed automatically
• Verified "Clear History" removes all entries
• Verified history resets after page refresh
• Verified responsive layout on mobile view
• Verified bun run lint, bunx tsc --noEmit, and bun run build all pass successfully

Fixes #676

Related Issue

Closes #676

Type of Contribution

• New feature
• GSSoC contribution

Participant Info

• GitHub username: imuniqueshiv
• Contribution level: Intermediate

Screen Recording

Recording / Loom link:

issue_reframe.1.mp4

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, @imuniqueshiv!

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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• Linked the issue this PR closes (e.g. Closes #123)
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Happy coding! 🎉

[github-actions]

✅ PR Format Check Passed — @imuniqueshiv

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