Adds fleet.status and fleet.sync ops (admin) and a /fleet page: last round, artifacts, parse fallbacks, and consecutive failures per store. With eleven repos a wedged store is invisible on a page that shows only counts — its counts are whatever they were when it broke.

gate gains gateAt so the fleet pages can ask for Admin at an empty repo rather than Token at a repo; forbid now words the refusal to match. check-in: 5c9f9f41b1 user: dmestas tags: trunk