Refactor back to a more modular configuration

modules/home-manager/cli/notes.nix

@@ -0,0 +1,30 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+with lib;
+
+let
+  cfg = config.homeManagerModules.cli.notes;
+in
+{
+  options.homeManagerModules.cli.notes.enable = mkEnableOption "Enable notes";
+
+  config = mkIf cfg.enable {
+    xdg = {
+      enable = true;
+      userDirs.enable = true;
+    };
+
+    home = {
+      packages = with pkgs; [ notes ];
+
+      sessionVariables = {
+        NOTES_DIRECTORY = "${config.xdg.userDirs.documents}/wiki/notes";
+      };
+    };
+  };
+}