The page reads a subscribed node's message counts from it too, and
draws them as dots on the map, as this node's own.
Auth plan M3 (live data from every reachable node).
Double-click a node to subscribe: the page reads its own links from it
directly with a narrowed token (reading the member list only), drawn
over what this node knows; kept per swarm in the browser.
Auth plan M3.