Hide the Traffic / Routing, Deployments, Federation and Secrets Fleet
tabs by default. They re-appear when the operator opts in by setting
SENCHO_EXPERIMENTAL=true. Backend routes and database tables are
unchanged; this is a UI discovery gate only.
The /api/meta endpoint now returns experimental as a boolean. A new
useExperimental hook reads it once per page load and feeds the four
tab triggers and tab content panels in FleetView.
Anso