Add Niri, a scrolling tiling window manager.

modules/home/wms/niri/inputs/default.nix

@@ -0,0 +1,20 @@
+{ pkgs, ... }:
+{
+  config.home.niri.settings.inputs = pkgs.writeText "inputs" ''
+    input {
+      mouse {
+        accel-profile "flat"
+        accel-speed -0.9
+      }
+      touchpad {
+        accel-profile "flat"
+        scroll-method "two-finger"
+      }
+      trackpoint {
+        off
+      }
+      warp-mouse-to-focus
+      focus-follows-mouse
+    }
+  '';
+}