The change watcher (#73673) missed one always-on-while-mounted timer: the
Messaging page polled /api/messaging/platforms every 6s for connection
status. The gateway already persists platform connect/disconnect/health to
gateway_state.json, so watch that file's mtime and broadcast
platforms.changed (floored to 5s — the gateway also rewrites the file for
in-flight-count bookkeeping), route it through live-sync like its
siblings, and refresh the page on the tick. Older backends keep the
legacy visible-tab poll verbatim.
Finishes the always-on poll sweep for #73618.
Brooklyn Nicholson
f8e07a332e