add COSMIC and system76 packages

hosts/x86_64/lemp13.nix

@@ -3,8 +3,23 @@
 {
     # Name your host machine
     networking.hostName = "lemp13"; 
-
+    
     # System76
-    hardware.system76.enableAll = true;
-}
+    environment.systemPackages = with pkgs; [
+        system76-keyboard-configurator
+        firmware-manager
 
+        # COSMIC Utils
+        cosmic-ext-tweaks
+        cosmic-ext-forecast
+        cosmic-ext-tasks
+        cosmic-ext-calculator
+        cosmic-ext-examine
+        stellarshot
+    ];
+
+    # COSMIC
+    services.desktopManager.cosmic.enable = true;
+    services.displayManager.cosmic-greeter.enable = true;
+
+}