Upgrades from ≤v2026.9.14 keep a cached root utils without file_signature
(narrow package-prefix purge). The post-pull gateway restart then imports
fresh hermes_cli.config and dies with ImportError, failing the daily
Install & Update E2E hermes-update legs. Drop the incomplete utils cache
before that import so the one pre-handoff upgrade can complete.
Co-authored-by: Samik Bandyopadhyay <callsamik@users.noreply.github.com>
