collate recent changes back to master

system/modules/wm.nix

@@ -0,0 +1,27 @@
+{
+  pkgs,
+  mainUser,
+  inputs,
+  ...
+}:
+{
+  services.greetd = {
+    enable = true;
+    restart = false;
+    settings =
+      let
+        session = {
+          command = "niri-session";
+          user = "${mainUser}";
+        };
+      in
+      {
+        default_session = session;
+        initial_session = session;
+      };
+  };
+  programs.niri = {
+    enable = true;
+    package = inputs.niri.packages.${pkgs.system}.niri-unstable;
+  };
+}