Next.js 16 nests standalone output under the project directory name when NEXT_TRACING_ROOT_MODE=workspace (e.g. standalone/9router/server.js instead of standalone/server.js), causing build-cli.js to fail with "Next.js standalone build not found". Detect nested layout with backward-compatible fallback to existing standalone/server.js and standalone/app/ paths. Co-authored-by: Cursor <cursoragent@cursor.com>