Egress probe results (IP/country/region/city/isp) were cached using the
fetcher's cache_ttl (300s / 5min). After 5 minutes the cache expired and
the node list showed empty Egress IP/Country/Region fields again.
Add a dedicated egress_cache_ttl config (default 24h) so egress data
persists long enough to be useful when re-expanding the node list.