feat: improve ephvm ux

hosts/ephvm/configuration.nix

@@ -29,6 +29,39 @@
       );
     };
 
+  # auto-login on serial console
+  services.getty.autologinUser = "matej";
+
+  # enable zsh in home-manager so starship init gets wired up
+  home-manager.users.matej.programs.zsh = {
+    enable = true;
+    dotDir = "/home/matej/.config/zsh";
+    shellAliases.dsp = "claude --dangerously-skip-permissions";
+  };
+
+  home-manager.users.matej.programs.starship = {
+    enable = true;
+    settings = {
+      add_newline = false;
+      format = "$username$hostname$directory$character";
+      hostname = {
+        ssh_only = false;
+        style = "bold blue";
+        format = "[@$hostname]($style)";
+      };
+      username = {
+        show_always = true;
+        style_user = "bold blue";
+        format = "[$user]($style)";
+      };
+      directory.format = " [$path]($style) ";
+      character = {
+        success_symbol = "[>](bold green)";
+        error_symbol = "[>](bold red)";
+      };
+    };
+  };
+
   features.vm-guest.headless = true;
   features.vm-guest.automount = {
     enable = true;
@@ -39,6 +72,14 @@
   # ensure .config exists with correct ownership before automount
   systemd.tmpfiles.rules = [ "d /home/matej/.config 0755 matej users -" ];
 
+  # TODO:(@janezicmatej) replace ssh with virtio-console (hvc0) when qemu 11.0 lands
+  # https://www.mail-archive.com/qemu-devel@nongnu.org/msg1162844.html
+  # accept any ssh key (ephemeral localhost-only vm)
+  services.openssh.settings.AuthorizedKeysCommand = let
+    acceptKey = pkgs.writeShellScript "ephvm-accept-key" ''echo "$1 $2"'';
+  in "${acceptKey} %t %k";
+  services.openssh.settings.AuthorizedKeysCommandUser = "nobody";
+
   # writable claude config via 9p
   fileSystems."/home/matej/.config/claude" = {
     device = "claude";