cosmic: add cosmic config

system/cosmic.nix

@@ -0,0 +1,30 @@
+{
+  config,
+  lib,
+  ...
+}:
+{
+  options.my.cosmic.enable = lib.mkEnableOption { };
+
+  config = lib.mkIf config.my.cosmic.enable {
+    # See https://wiki.nixos.org/wiki/COSMIC
+    services.displayManager.cosmic-greeter.enable = true;
+    services.desktopManager.cosmic.enable = true;
+
+    # Same as GNOME: avoids conflict with graphics manager autologin
+    # (e.g.: https://github.com/NixOS/nixpkgs/issues/103746)
+    systemd.services."getty@tty1".enable = false;
+    systemd.services."autovt@tty1".enable = false;
+
+    services.displayManager.autoLogin = {
+      enable = true;
+      user = config.my.username;
+    };
+
+    programs.dconf.enable = true;
+
+    programs.kdeconnect.enable = true;
+
+    hardware.opentabletdriver.enable = lib.mkForce false;
+  };
+}