9febb23bc9
Prevent data loss and nil panics across 5 parse functions: - chain: nil-guard hop entries to avoid deref on empty YAML lists - hop: build merged metadata map instead of writing inherited values into the original NodeConfig; swap+restore around ParseNode call - node: use local connCfg/dialCfg instead of overwriting cfg.Connector and cfg.Dialer fields; only fill in Type when empty - parser: preserve existing config file fields when env vars override Level/Addr (was replacing the entire struct) - router: only update ipNet from dst CIDR if parse succeeds, keeping the route.Net fallback instead of overwriting with nil