add avahi support

configuration.nix

@@ -81,6 +81,19 @@
   # Enable CUPS to print documents.
   services.printing.enable = true;
 
+  services.avahi = {
+    enable = true;
+    nssmdns = true;
+    publish = {
+      enable = true;
+      addresses = true;
+      domain = true;
+      hinfo = true;
+      userServices = true;
+      workstation = true;
+    };
+  };
+
   # Enable sound with pipewire.
   # sound.enable = true;
   hardware.pulseaudio.enable = false;