Fix btoa emoji crash

[divyansha12]

Hey @magic-peach

Description

Fixes a fatal DOMException crash when clicking "Copy Link" after adding a text overlay
containing emojis or non-ASCII characters. The native btoa() only accepts Latin1 characters,
so emoji in the JSON string caused an immediate unhandled exception with no user feedback.

Fix: Wraps JSON.stringify(recipe) with encodeURIComponent + unescape before
btoa(), and decodes symmetrically with escape + decodeURIComponent after atob().
Exports encodeRecipe from useVideoEditor.ts and uses it in VideoEditor.tsx's
handleCopyLink, replacing the crashing direct btoa() call.

Related Issue

Closes #1469

Type of Contribution

• Bug fix
• GSSoC contribution

Participant Info

• GitHub username: divyansha12
• Contribution level: Intermediate

Checklist

• I have read the contribution guidelines
• My changes follow the project structure
• No console.log statements left in
• This PR is related to a valid issue

[vercel]

@divyansha12 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]

⚠️ PR Format Issues — @divyansha12

Please fix the following before your PR can be reviewed:

• ⚠️ Use a conventional PR title. Examples:
  • feat: add dark mode support
  • fix: resolve aria label missing on slider
  • docs: add deployment guide to README

Push new commits after fixing — this comment will update automatically.

📖 CONTRIBUTING.md

[github-actions]

👋 Thanks for your PR, @divyansha12!

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! 🎉