microsoft/inshellisense ? reverse-engineered prompt

Build me a terminal autocomplete tool that feels like IDE suggestions, but works right inside the shell.

I want it to support the common shells on Windows, macOS, and Linux, and make command typing faster with inline suggestions, a small suggestion list, and descriptions for commands when available. It should be easy to install, easy to start from the terminal, and have a simple setup command that can add itself to my shell config so it opens automatically in new sessions.

Please include a basic config file so I can change things like key bindings, how many suggestions show at once, whether alias expansion is on, and a few visual options like colors and rounded borders. Also add a doctor style check so I can verify everything is working.

If you need to look up current docs online for any shell specific behavior, go ahead.