feat(edaas): set hostName to emmathorpe-edaas

The host inherited the stock NixOS default hostname 'nixos', which does not
match the flake's nixosConfigurations attribute 'emmathorpe-edaas'. nh
selects the configuration by the local hostname, so bare 'nh os switch'
failed to resolve. Pin the hostname to the attribute name so it resolves
without an explicit -H/--hostname flag.

system/machine/EDaaS/configuration.nix

@@ -43,6 +43,11 @@
     autoPrune.enable = true;
   };
 
+  # Match the flake's nixosConfigurations attribute name so `nh os switch`
+  # (which selects by the local hostname) resolves without an explicit
+  # -H/--hostname flag. The default would otherwise be the stock NixOS "nixos".
+  networking.hostName = "emmathorpe-edaas";
+
   networking.resolvconf.enable = false;
 
   # Drop the systemd-ssh-proxy Include from the generated /etc/ssh/ssh_config.