add demo_iso code for iso-morphing

flakeModules/demo_template/configuration.nix

@@ -0,0 +1,38 @@
+{ pkgs, config, ... }:
+{
+  fileSystems."/".device = "nodev";
+  boot.loader.grub.device = "nodev";
+  clan.core.vars.settings.secretStore = "fs";
+  clan.core.vars.generators.mycelium = {
+    files."key" = { };
+    files."ip".secret = false;
+    files."pubkey".secret = false;
+    runtimeInputs = [
+      pkgs.mycelium
+      pkgs.coreutils
+      pkgs.jq
+    ];
+    script = ''
+      timeout 5 mycelium --key-file "$out"/key || :
+      mycelium inspect --key-file "$out"/key --json | jq -r .publicKey > "$out"/pubkey
+      mycelium inspect --key-file "$out"/key --json | jq -r .address > "$out"/ip
+    '';
+  };
+  services.mycelium = {
+    enable = true;
+    addHostedPublicNodes = true;
+    openFirewall = true;
+    keyFile = config.clan.core.vars.generators.mycelium.files.key.path;
+  };
+  services.getty.autologinUser = "root";
+  programs.bash.interactiveShellInit = ''
+    if [[ "$(tty)" =~ /dev/(tty1|hvc0|ttyS0)$ ]]; then
+      # workaround for https://github.com/NixOS/nixpkgs/issues/219239
+      systemctl restart systemd-vconsole-setup.service
+
+      reset
+
+      your mycelium IP is: $(cat /var/lib/mycelium/ip)
+    fi
+  '';
+}