try better cgroups for fuzzel apps

note that this only half works because niri won't put the process in the
cgroup if it forks too quickly

home-manager/home.nix

@@ -3,6 +3,7 @@
 
 { pkgs
 , inputs
+, lib
 , ...
 }:
 let
@@ -67,6 +68,12 @@ in
         exec swaylock
       '';
     })
+    (pkgs.writeShellApplication {
+      name = "fuzzel-in-niri";
+      text = ''
+        ${lib.getExe pkgs.fuzzel} --launch-prefix "${lib.getExe pkgs.niri} msg action spawn --"
+      '';
+    })
     (pkgs.writeShellApplication {
       name = "shell.nix";
       text = ''