Install pnpm instead of yarn
diff --git a/modules/node.nix b/modules/node.nix
index 0de7e98..68de5ce 100644
--- a/modules/node.nix
+++ b/modules/node.nix
@@ -2,7 +2,7 @@
   environment.systemPackages = with pkgs; [
     nodejs_20
     nodePackages.typescript
-    yarn
+    nodePackages.pnpm
     nodePackages.pm2
   ];
 }