revamp(quickstart): improve Node.js Express API quickstart DX

[arpit-jn]

Summary

Revamps the Node.js Express API quickstart to improve developer experience (DX) and align with the modern Auth0 quickstart format (similar to React SPA quickstart).

Changes

Structure & Format

• Added proper frontmatter (mode: wide, title, description, sidebarTitle)
• Restructured content into 8 numbered <Steps> and <Step> components for clear progression
• Added <Tabs> component for CLI vs Dashboard setup options
• Added <AuthCodeGroup> for Mac/Windows CLI command switching
• Converted non-standard ::: note and ::: warning syntax to JSX components (<Note>, <Info>, <Warning>)

Content Improvements

• Added clear prerequisites section at the top
• Added complete server example with all code consolidated
• Added Access Token claims section showing how to access req.auth
• Added TypeScript support with full example
• Added additional configuration options documentation
• Added security best practices (Helmet, production error handling)
• Added troubleshooting table with common issues and solutions
• Added Next Steps with links to related documentation

Developer Experience

• Step-by-step tutorial format (1-8 numbered steps)
• One-command CLI setup that creates .env file automatically
• Clear code examples with syntax highlighting
• Copy-paste ready curl commands for testing
• Environment variable validation in code examples

Testing

• Verified MDX syntax is valid (no parsing errors)
• Verified all JSX components are properly opened/closed
• Verified frontmatter format matches other quickstarts
• Verified code examples are complete and runnable
• Verified links to Auth0 documentation are valid

Related

• Follows the same format as: https://auth0.com/docs/quickstart/spa/react
• SDK documentation: https://github.com/auth0/node-oauth2-jwt-bearer

Checklist

• Code follows project style guidelines
• Self-reviewed the changes
• No breaking changes to existing functionality
• Documentation is clear and complete

[github-actions]

Summary

Status	Count
🔍 Total	10
✅ Successful	5
⏳ Timeouts	0
🔀 Redirected	3
👻 Excluded	2
❓ Unknown	0
🚫 Errors	0
⛔ Unsupported	0

Redirects per input

Redirects in main/docs/quickstart/backend/nodejs/interactive.mdx

• [200] https://jwt.io/ | Redirect: Followed 1 redirect resolving to the final status of: OK. Redirects: https://jwt.io/ --> https://www.jwt.io/
• [200] https://nodejs.org/ | Redirect: Followed 1 redirect resolving to the final status of: OK. Redirects: https://nodejs.org/ --> https://nodejs.org/en
• [200] https://npmjs.com/ | Redirect: Followed 1 redirect resolving to the final status of: OK. Redirects: https://npmjs.com/ --> https://www.npmjs.com/
  Full Github Actions output