filiksyos/gitreverse ? reverse-engineered prompt

Build me a simple web app that can "reverse engineer" a GitHub repository. The main idea is to take a public repo's URL and generate a synthetic prompt that someone might have used to create it with an AI coding assistant.

The user interface should be clean and straightforward: just a single page with an input box. A user can paste in a full GitHub URL or a shorthand like owner/repo. I'd also like it to support shareable routes, so a URL like /vercel/next.js would automatically run the analysis for that repo.

On the backend, it will need to use the GitHub API to fetch the repo's metadata, its root file tree, and the README content. Then, it should pass all that context to a large language model using OpenRouter to generate the final prompt.

Let's build this with Next.js using the App Router, React, and TypeScript. For styling, please use Tailwind CSS to keep it modern and minimal.