The poll had no hidden-tab gate, and the local scan's 5 s cache sits under the
8 s interval, so a single tab never hit it: every tick was a full socket sweep
(1.1 s and 772 forks on a box with 212 sockets) for a list nobody was reading.
`_foreignPollTick()` is now the one gate for the first load, the timer and the
return to a visible tab. The `visibilitychange` listener is stored and removed
in `stopForeignPolling()`, since this runs on every trip to the home screen.
Checked in real chromium with document.hidden stubbed: 2 polls in 9.5 s visible,
0 in 17.5 s hidden, 1 on return, and a tab opened in the background makes none
until it is shown.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Codeman maintainer
9714ee79e8