fix: resolve sma user definition conflict between modules

- Remove duplicate sma user definition from incus.nix module
- The sma user is properly defined in modules/users/sma.nix with incus-admin group
- This resolves the isNormalUser/isSystemUser assertion failure blocking congenital-optimist rebuild
- Clean up grey-area configuration and modularize services
- Update SSH keys with correct IP addresses for grey-area and reverse-proxy

modules/virtualization/incus.nix

@@ -10,10 +10,6 @@
     incus
     lxc
   ];
-  users.users.geir = {
-    extraGroups = [ 
-      "incus-admin"
-    ];
-  };
+  
   networking.firewall.allowedTCPPorts = [ 8443 ];
 }