Moving Factorio Off playit.gg: One Game Port on the Owned Tunnel, Named on Both Tiers

Overview

Factorio's public access has ridden playit.gg since V2: a third-party tunnel agent in the pod, a rented hostname, and a secret to match. The edge we built in Public Tier HTTPS makes that redundant. This appendix puts the game on the owned tunnel for WAN players, names it on the private tier for the household, and retires the playit sidecar and its secret entirely.