fix(nest): stop declaring require twice in the CommonJS steps bundle

[torsello]

Description

Fixes #3778.

workflow-nest build --module commonjs writes a steps bundle that declares require twice, so importing it throws SyntaxError: Identifier 'require' has already been declared. The build reports success, so the failure surfaces later and indirectly — the flow route answers 500 and the run stays pending.

#rewriteStepsBundleForCjs prepends its own createRequire shim, but createStepsBundle already emits an ESM interop banner declaring the same binding. Nest passes bundleFinalOutput: false, so skipEsmRequireBanner stays false and the banner is always there.

The shim is redundant, so this drops it. Skipping the banner instead — the fix the issue suggests — would also drop __filename/__dirname, which createStepsBundle explicitly warns against in its JSDoc.

How did you test your changes?

Built workbench/nest with --module commonjs, before and after.

Before — build succeeds, bundle does not parse:

$ node packages/nest/dist/cli.js build --module commonjs --dirs src/workflows
✓ Compiled workflows in 1.0s (152 steps, 164 workflows)

$ sed -n '1,8p' .nestjs/workflow/steps.mjs
import { createRequire as __bundled_createRequire } from 'node:module';
const require = __bundled_createRequire(import.meta.url);
// biome-ignore-all lint: generated file
/* eslint-disable */
import { createRequire as __createRequire } from "node:module";
...
var require = __createRequire(import.meta.url);

$ node --check .nestjs/workflow/steps.mjs
SyntaxError: Identifier 'require' has already been declared

After — one declaration, parses clean:

$ sed -n '1,8p' .nestjs/workflow/steps.mjs
// biome-ignore-all lint: generated file
/* eslint-disable */
import { createRequire as __createRequire } from "node:module";
import { fileURLToPath as __fileURLToPath } from "node:url";
import { dirname as __pathDirname } from "node:path";
var require = __createRequire(import.meta.url);
var __filename = __fileURLToPath(import.meta.url);
var __dirname = __pathDirname(__filename);

$ grep -cE '(const|var|let) require =' .nestjs/workflow/steps.mjs
1

$ node --check .nestjs/workflow/steps.mjs   # exits 0

__filename/__dirname are still shimmed, since the banner is the one providing them.

Importing the bundle in this workbench then fails on MODULE_NOT_FOUND for ../../example/workflows/*.js — those live outside the app's src/, so they never land in its dist/. That is the shared-workbench layout, unrelated to this change; without the fix the bundle never parses far enough to attempt resolution at all.

pnpm --filter @workflow/nest test passes (35 tests), biome check is clean on the touched file.

[changeset-bot]

🦋 Changeset detected

Latest commit: f22da80

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 16 packages

Name	Type
@workflow/nest	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/core	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/vitest	Patch
@workflow/web-shared	Patch
@workflow/web	Patch
@workflow/astro	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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[torsello]

@vercel/workflow ready for review