The E2E account is now admin (matching the real primary user), so the nav spec
also drives scheduler/config/users/audit — exercising the render ternary's admin
branches, which the upcoming PageShell refactor will restructure.
Locks the five flows the refactor must not break (feed, channel, player,
settings, nav) so later sprints can prove they changed nothing. Adds a thin
data-testid layer and a dedicated seeded non-demo account; the suite runs on
the baked :8080 stack (authoritative) or :5173. No product-behaviour change.
peter