A worker thread asks GitHub's API about update_check_repo: the latest release
and, for development and CI builds, how far the build's commit is behind its
branch (or main). Unauthenticated, with ETags, every update_check_interval_hours
(default 6); offline or rate limited, the last answer stays next to the error
and a used-up limit waits for its reset. The main loop logs results, sends
them to master (UPDATE_STATUS, again when the link comes back) and pushes
update_check to open pages. GET /api/update_check, and
POST /api/update_check/check (settings permission, once a minute). Nothing is
downloaded or installed.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
