import.meta.url is undefined when esbuild bundles to CJS format (format: 'cjs' in build.ts). fileURLToPath(undefined) throws ERR_INVALID_ARG_TYPE which crashed the production server on startup. Fix: drop the _dirname derivation entirely and resolve TIMMY_TEST_PLAN.md relative to process.cwd(), which is always the workspace root in both: - dev: tsx runs from workspace root - production: pnpm --filter ... run start runs from workspace root Also removes the now-unused 'dirname' and 'fileURLToPath' imports. Verified: rebuilt dist/index.cjs — 0 import.meta.url references remain. GET /api/testkit/plan returns HTTP 200 from the production bundle.