The Fleet UI only showed TEARDOWN for swarm-pinned deckies (POST
/swarm/hosts/{uuid}/teardown). Local deckies had no delete control though
the API now exposes DELETE /deckies/{name}.
teardown() branches on swarm vs local; the card's two-step arm/CONFIRM
button renders for any admin, keyed td:${host_uuid ?? 'local'}:${name}.