vercel-fieldeng/order-platform-demo ? reverse-engineered prompt

Build me a multi tenant web app in Next.js where the main domain shows a landing page and admin area, and each tenant gets its own subdomain with its own branded content and pages. I want the app to detect the subdomain automatically, route users to the right tenant experience, and keep tenant data in Redis. The admin panel should let me create and manage tenants, including things like tenant names and emoji branding, and the shared layout and components should be reused across the whole app.

Make it work well for local development with subdomains, and make sure it is ready for Vercel deployment and preview deployments too. Use a clean modern UI that feels production ready, and if you need to check current docs for Next.js or deployment details, look them up online.