One "Teams" nav entry now, matching how Family has none of its own and
is only reached through Members -- Roster/Staff were pure club-wide
list stubs with no way to add/remove anyone except Django admin.
Opening a team shows its roster and staff for whichever season is
selected (?season=, defaulting to the current one, same pattern as the
Memberships page); adding/editing/removing either is gated to that
team's own manager or a club admin (TeamManagerRequiredMixin, defined
earlier but never actually wired up until now).
Bernard Siebens
a3e413904f