[launchers] Add launcher wrappers for compact env

Adds a module to launch specific nixpkgs dynamically, such that they
won't be always included in the nix store

home/roles/launchers/default.nix

@@ -0,0 +1,36 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.home.roles.launchers;
+
+  # Generate a wrapper script for a package
+  makeLauncher = packageName: pkgs.writeShellScriptBin packageName ''
+    exec env NIXPKGS_ALLOW_UNFREE=1 ${pkgs.nix}/bin/nix run --impure nixpkgs#${packageName} -- "$@"
+  '';
+
+  # Generate all launcher scripts from the package list
+  launcherPackages = map makeLauncher cfg.packages;
+in
+{
+  options.home.roles.launchers = {
+    enable = mkEnableOption "wrapper launchers for excluded packages";
+
+    packages = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      example = [ "steam" "libreoffice" "lutris" ];
+      description = ''
+        List of package names to create launcher wrappers for.
+        Each wrapper will run: NIXPKGS_ALLOW_UNFREE=1 nix run --impure nixpkgs#<package>
+
+        This is useful for occasionally running packages without permanently installing them.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = launcherPackages;
+  };
+}