yobiru-upgrade

Check for Yobiru updates from the official chekusu/yobiru releases, upgrade this machine safely (plugin, durable receiver runtime, receiver restart, Codex bridge), then notify the user's other known Yobiru installations with a versioned upgrade notice and track which ones converged. Also handles a received upgrade notice. Use when the user asks about Yobiru status, versions, updates or upgrades, sets up update reminders, or an inbox message has kind yobiru-upgrade-notice.