Add state version to apollo and cluster

hosts/cap-clust-07/configuration.nix

@@ -9,4 +9,12 @@
   ];
 
   networking.hostName = "cap-clust-07";
+
+  # This value determines the NixOS release from which the default
+  # settings for stateful data, like file locations and database versions
+  # on your system were taken. It‘s perfectly fine and recommended to leave
+  # this value at the release version of the first install of this system.
+  # Before changing this value read the documentation for this option
+  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
+  system.stateVersion = "25.11"; # Did you read the comment?
 }