The install event isn't delivered when the app replaces its own APK, so a
self-update could linger in the Updates list as "installing forever" after the
update completed and the app restarted.
- UpdateHelper: clear a stale self-update row on launch, flavor-aware — nightly
by its commit-tagged version name (the version code is static), release/preload
by the version code.
- DownloadHelper: finalize a self-update download stuck in INSTALLING (the commit
killed the process before it could advance) to INSTALLED on launch.
4a0c1101f4