sourcegraph/sourcegraph-public-snapshot ? reverse-engineered prompt

Build me a web app like Sourcegraph that helps people search and understand code across lots of repositories.

I want a clean homepage, a global search box, and pages where I can browse repositories, search for symbols or text, jump to definitions, see references, and view file history. It should feel useful for big codebases, so make navigation fast and the search results easy to scan. I also want a simple assistant style experience for helping with code questions and fixes, something that can explain code and suggest changes in context.

Please make it work as a self hosted product with a polished UI and a solid backend, and set it up so I can run it locally for development. If you need current implementation details or docs, look them up online first and then build the closest working version you can.