Add docs preview server for locally previewing documentation

[henrik-sky]

✅ What’s Working

• Local web server running at http://localhost:3000/
• Automatic image path conversion from GitHub raw URLs to local files
• Component browser with easy navigation
• GitHub-style markdown rendering with dark/light mode toggle
• Live preview - just edit files and refresh!

🚀 How to Use

• Start the server :
  • npm run preview-docs
• Open in browser: http://localhost:3000/
• Edit your markdown files and refresh to see changes instantly

🎨 Features

• Component listing: Browse all Compose and View components
• Theme toggle: Switch between light and dark modes
• Local screenshots: All your PNG files load directly from the repo
• Clean rendering: GitHub-flavored markdown with proper styling

📝 Perfect For

• Previewing your Button README changes before pushing
• Testing image links work correctly
• Reviewing documentation formatting
• Sharing docs with teammates locally

The server automatically converts those GitHub raw URLs (like https://raw.githubusercontent.com/Skyscanner/backpack-android/main/docs/compose/Button/screenshots/default.png) to local paths, so you can see your screenshots immediately without needing to push to GitHub first.

Just edit your markdown files, refresh the browser, and see your changes! When you’re happy with how everything looks, you can confidently push your changes. 🚀

• Check this if you have read and followed the contributing guidelines

Remember to include the following changes:

• Component README.md
• Tests

If you are curious about how we review, please read through the code review guidelines

[skyscanner-backpack-bot]

	Fails
🚫	These new files do not include the license heading: preview-server.js

Generated by 🚫 Danger Kotlin against 6ed702f