Ford P4 catalog navigation is session-stateful: catCode group.action returns
the full Ford model picker (30 vehicle.action rows), and vehicle.action?modelFamily=X
loops back to the same picker; a bare group.action after select still returns the
picker (parsedGroups=0). Stateless GETs over a rotating proxy can't hold PL24's
server-side model selection → groups are unreachable (explains 0/57 categories_fetched
on prod). Needs session-continuity or browser-based navigation — tracked, not a quick fix.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>