Main now keeps a per-machine data directory whose proddash.json can override
the port, so reading the repo's config file was no longer a safe way to find
the ProPresenter module's loopback feed. Guess the port the way the shell
does (PORT, data-dir proddash.json, repo proddash.json, 24500), then confirm
it from the Host header of the first tile request; a learned port that
refuses the connection (a reverse proxy) is blacklisted and the guess kept.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
