Add initial (and untested) river example config

home/river/default.nix

@@ -0,0 +1,51 @@
+{config, ...}: {
+  imports = [../desktop.nix];
+  wayland.windowManager.river = {
+    enable = true;
+    xwayland.enable = true;
+    extraSessionVariables = {
+      QT_AUTO_SCREEN_SCALE_FACTOR = "1";
+      QT_QPA_PLATFORM = "wayland";
+      QT_WAYLAND_DISABLE_WINDOWDECORATION = "1";
+      MOZ_ENABLE_WAYLAND = "1";
+    };
+    systemd = {
+      enable = true;
+      variables = [
+        "DISPLAY"
+        "WAYLAND_DISPLAY"
+        "XDG_CURRENT_DESKTOP"
+        "NIXOS_OZONE_WL"
+        "XCURSOR_THEME"
+        "XCURSOR_SIZE"
+      ];
+    };
+    settings = {
+      # These are currently example settings
+      border-width = 2;
+      declare-mode = [
+        "locked"
+        "normal"
+        "passthrough"
+      ];
+      input = {
+        pointer-foo-bar = {
+          accel-profile = "flat";
+          events = true;
+          pointer-accel = -0.3;
+          tap = false;
+        };
+      };
+      map = {
+        normal = {
+          "Alt Q" = "close";
+        };
+      };
+      rule-add = {};
+      set-cursor-warp = "on-output-change";
+      set-repeat = "50 300";
+      spawn = [];
+      xcursor-theme = with config.gtk.cursorTheme; "${name} ${toString size}";
+    };
+  };
+}

system/river.nix

@@ -0,0 +1,7 @@
+{}: {
+  imports = [./desktop.nix];
+  programs.river = {
+    enable = true;
+    extraPackages = [];
+  };
+}