Argo Workflows: ArtifactGC.PodSpecPatch bypasses Strict/Secure template reference allow-list (Incomplete fix for CVE-2026-31892)

Summary The allow-list fix for CVE-2026-31892 GHSA-3wf5-g532-rcrr, and its follow-up coverage of hostNetwork/securityContext/serviceAccountName in GHSA-3775-99mw-8rp4, is incomplete. workflow/util/merge.go ValidateUserOverrides / SanitizeUserWorkflowSpec walk only the top-level fields of...