docs: add README project snapshot

[saurabhhhcodes]

Summary

• add a Project Snapshot table near the top of the README
• highlight stack, privacy model, setup, deployment, license, and contribution status
• add a direct onboarding pointer to Getting Started and CONTRIBUTING.md

Closes #843

Verification

• git diff --check

[vercel]

Someone 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, @saurabhhhcodes!

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

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 — @saurabhhhcodes

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.