_cold_start_windows_gateway_after_update cleared the dead attestation as soon
as _spawn_detached() returned a PID, before _wait_for_gateway_ready() proved
the gateway survived. When readiness failed, the RuntimeError registered the
retry, but the retry then saw Desktop lifecycle ownership with no marker and
returned success without spawning anything — the silent outage of #109538
came back through the retry path (#110020 review). The marker is now
consumed after readiness is confirmed, so a failed spawn leaves the retry
its recovery obligation.
kshitijk4poor
ccc335cdba