page-serve, give a human a URL

An agent that renders a page for a human needs a way to hand it over. The pattern that grew in sessions was python3 -m http.server 8991 plus portless alias <name> 8991 typed by hand: no record of the process, no stop, servers outliving the session, and one measured night (2026-09-06) where the same session did it twice and the server was still up the next morning. This skill is that pattern with a state file, a stop, a status, and a loud failure when the URL contract cannot be met.

The contract