fix: n8n build error

pkgs/n8n/default.nix

@@ -1,22 +1,8 @@
-{
-  stdenv,
-  lib,
-  nixosTests,
-  fetchFromGitHub,
-  nodejs,
-  pnpm_10,
-  fetchPnpmDeps,
-  pnpmConfigHook,
-  python3,
-  node-gyp,
-  cctools,
-  xcbuild,
-  libkrb5,
-  libmongocrypt,
-  libpq,
-  makeWrapper,
-}:
-stdenv.mkDerivation (finalAttrs: {
+{ stdenv, lib, nixosTests, fetchFromGitHub, nodejs, pnpm_10, fetchPnpmDeps
+, pnpmConfigHook, python3, node-gyp, cctools, xcbuild, libkrb5, libmongocrypt
+, libpq, makeWrapper, }:
+let python = python3.withPackages (ps: with ps; [ websockets ]);
+in stdenv.mkDerivation (finalAttrs: {
   pname = "n8n";
   version = "2.8.3";
 
@@ -34,15 +20,13 @@ stdenv.mkDerivation (finalAttrs: {
     hash = "sha256-gX4pYiztKIRFbJNZhtQviWpp80teOzX1JaYKylGe4TY=";
   };
 
-  nativeBuildInputs =
-    [
+  nativeBuildInputs = [
     pnpmConfigHook
     pnpm_10
     python3 # required to build sqlite3 bindings
     node-gyp # required to build sqlite3 bindings
     makeWrapper
-    ]
-    ++ lib.optional stdenv.hostPlatform.isDarwin [cctools xcbuild];
+  ] ++ lib.optional stdenv.hostPlatform.isDarwin [ cctools xcbuild ];
 
   buildInputs = [ nodejs libkrb5 libmongocrypt libpq ];
 
@@ -80,11 +64,22 @@ stdenv.mkDerivation (finalAttrs: {
     runHook preInstall
 
     mkdir -p $out/{bin,lib/n8n}
-    mv {packages,node_modules} $out/lib/n8n
+    cp -r {packages,node_modules} $out/lib/n8n
 
     makeWrapper $out/lib/n8n/packages/cli/bin/n8n $out/bin/n8n \
       --set N8N_RELEASE_TYPE "stable"
 
+    # JavaScript runner
+    makeWrapper ${nodejs}/bin/node $out/bin/n8n-task-runner \
+      --add-flags "$out/lib/n8n/packages/@n8n/task-runner/dist/start.js"
+
+    # Python runner
+    mkdir -p $out/lib/n8n-task-runner-python
+    cp -r packages/@n8n/task-runner-python/* $out/lib/n8n-task-runner-python/
+    makeWrapper ${python}/bin/python $out/bin/n8n-task-runner-python \
+      --add-flags "$out/lib/n8n-task-runner-python/src/main.py" \
+      --prefix PYTHONPATH : "$out/lib/n8n-task-runner-python"
+
     runHook postInstall
   '';
 
@@ -99,13 +94,15 @@ stdenv.mkDerivation (finalAttrs: {
   dontRewriteSymlinks = true;
 
   meta = {
-    description = "Free and source-available fair-code licensed workflow automation tool";
+    description =
+      "Free and source-available fair-code licensed workflow automation tool";
     longDescription = ''
       Free and source-available fair-code licensed workflow automation tool.
       Easily automate tasks across different services.
     '';
     homepage = "https://n8n.io";
-    changelog = "https://github.com/n8n-io/n8n/releases/tag/n8n@${finalAttrs.version}";
+    changelog =
+      "https://github.com/n8n-io/n8n/releases/tag/n8n@${finalAttrs.version}";
     maintainers = with lib.maintainers; [ gepbird AdrienLemaire sweenu ];
     license = lib.licenses.sustainableUse;
     mainProgram = "n8n";