fix: egress cache TTL independent from fetcher cache (24h default)

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.

internal/handler/egress_info.go

@@ -66,9 +66,9 @@ func (d *Deps) HandleEgressInfo(c fiber.Ctx) error {
 	}
 	info["cached"] = false
 	if data, err := json.Marshal(info); err == nil {
-		ttl := int(d.Cfg.Fetcher.CacheTTL.Seconds())
+		ttl := int(d.Cfg.Fetcher.EgressCacheTTL.Seconds())
 		if ttl <= 0 {
-			ttl = 300
+			ttl = 86400 // 24h default
 		}
 		d.CacheRepo.SafePut(cacheKey, string(data), nil, ttl)
 	}