feat: improve display assertions

home/options.nix

@@ -115,8 +115,12 @@
         message = "a non-headless system can't be minimal";
       }
       {
-        assertion = config.eisfunke.displays.main.id != null;
-        message = "the main display needs to have an id specified";
+        assertion = !config.eisfunke.headless -> config.eisfunke.displays.main != null;
+        message = "a non-headless system needs to have main display configured";
+      }
+      {
+        assertion = !config.eisfunke.headless -> (config.eisfunke.displays.main.id != null && config.eisfunke.displays.main.name != null);
+        message = "the main display needs to have both a name and an id specified";
       }
     ];
   };