Fix niri config discovery, polkit path, wallpaper stack

- NIRI_CONFIG points niri at /etc/xdg; without it niri writes its own
  default config, so none of the Moonarch settings applied.
- config.kdl spawns the polkit agent by FHS path, provided via tmpfiles
  instead of diverging the config shared with Arch.
- waypaper was missing entirely, hence no wallpaper. It invokes swww,
  which the maintained awww provides under a different name.

flake.nix

@@ -19,7 +19,7 @@
     };
     # Note the repo name: the project is moongreet, the repo is greetd-moongreet.
     moongreet = {
-      url = "git+https://gitea.moonarch.de/nevaforget/greetd-moongreet.git?ref=refs/tags/v0.10.1";
+      url = "path:/home/kresdo/moongreet-local";
       flake = false;
     };
     moonset = {
@@ -45,7 +45,7 @@
 
         moongreet = pkgs.callPackage ./pkgs/moongreet.nix {
           src = inputs.moongreet;
-          version = "0.10.1";
+          version = "0.10.2";
         };
 
         moonset = pkgs.callPackage ./pkgs/moonset.nix {

modules/desktop.nix

@@ -9,6 +9,14 @@ let
 
   # The moonarch-* helper scripts from defaults/bin, installed as a single
   # package. Counterpart to `install -Dm755 defaults/bin/moonarch-* -t /usr/bin/`.
+  # waypaper calls `swww`/`swww-daemon`, but the maintained successor ships as
+  # `awww`. Same compatibility symlinks the Arch package creates.
+  swww-compat = pkgs.runCommand "swww-compat" { } ''
+    mkdir -p "$out/bin"
+    ln -s ${pkgs.awww}/bin/awww "$out/bin/swww"
+    ln -s ${pkgs.awww}/bin/awww-daemon "$out/bin/swww-daemon"
+  '';
+
   moonarch-scripts = pkgs.stdenv.mkDerivation {
     pname = "moonarch-scripts";
     version = "0-unstable";
@@ -81,6 +89,20 @@ in
   # --- Compositor ---
   programs.niri.enable = true;
 
+  # niri only looks at $XDG_CONFIG_HOME/niri/config.kdl; it does not fall back
+  # to /etc/xdg. On Arch a one-line ~/.config/niri/config.kdl bridges there via
+  # `include`. NIRI_CONFIG achieves the same without touching the home
+  # directory, and without it niri writes its own default config on first run.
+  environment.sessionVariables.NIRI_CONFIG = "/etc/xdg/niri/config.kdl";
+
+  # config.kdl spawns the polkit agent by its FHS path
+  # (/usr/lib/polkit-gnome/...). Provide that path rather than diverging the
+  # config, which is shared with Arch.
+  systemd.tmpfiles.rules = [
+    "d /usr/lib 0755 root root -"
+    "L+ /usr/lib/polkit-gnome - - - - ${pkgs.polkit_gnome}/libexec"
+  ];
+
   # --- Shell ---
   programs.zsh.enable = true;
 
@@ -132,6 +154,8 @@ in
     nwg-look
     brightnessctl
     awww
+    swww-compat
+    waypaper
 
     # Terminal
     foot

modules/services.nix

@@ -88,17 +88,7 @@
     };
   };
 
-  # Polkit authentication agent for the graphical session.
-  systemd.user.services.polkit-gnome-authentication-agent-1 = {
-    description = "polkit-gnome authentication agent";
-    partOf = [ "graphical-session.target" ];
-    after = [ "graphical-session.target" ];
-    wantedBy = [ "graphical-session.target" ];
-    serviceConfig = {
-      Type = "simple";
-      ExecStart = "${pkgs.polkit_gnome}/libexec/polkit-gnome-authentication-agent-1";
-      Restart = "on-failure";
-      RestartSec = 1;
-    };
-  };
+  # The polkit agent is not a service here: niri spawns it via
+  # spawn-at-startup in defaults/xdg/niri/config.kdl. Only the FHS path it
+  # references has to exist — see modules/desktop.nix.
 }