Extend dots.ports module to remaining NixOS hosts

- hetznix02: import shared ports, derive firewall via lib.pipe, wire
  node-exporter and nginx-exporter port references in monitoring.nix
- kiosk-entryway: import shared ports, wire node-exporter port in monitoring.nix
- kiosk-gene-desk: import shared ports, make node-exporter port explicit
- bigboy, rainbow-planet: import shared ports for consistency

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

modules/hosts/nixos/kiosk-entryway/monitoring.nix

@@ -16,7 +16,7 @@ in
           {
             job_name = "node";
             static_configs = [
-              { targets = [ "127.0.0.1:9100" ]; }
+              { targets = [ "127.0.0.1:${toString config.dots.ports.node-exporter.port}" ]; }
             ];
             metric_relabel_configs = [
               {
@@ -63,7 +63,7 @@ in
     prometheus.exporters.node = {
       enable = true;
       listenAddress = "127.0.0.1";
-      port = 9100;
+      inherit (config.dots.ports.node-exporter) port;
       extraFlags = [
         "--collector.filesystem.mount-points-exclude=^/(sys|proc|dev|run|tmp|var/lib/docker/.+)($|/)"
         "--collector.diskstats.device-exclude=^(loop|ram|fd|sr|dm-|nvme[0-9]n[0-9]p[0-9]+_crypt)$"