Envoy Gateway's per-route default timeout (15s, unset anywhere in this
cluster) was cutting the connection to argocd-server mid-Sync, surfacing
as 'Gateway Timeout' in the UI — confirmed even a single-resource sync
hit exactly ~15.0s every attempt, ruling out chart size/congestion.
BackendTrafficPolicy on the argocd HTTPRoute raises requestTimeout to 120s.
