Support npm 12 pack metadata in the onboarding fixture #651

Why

The existing packed onboarding fixture fails before exercising the SDK when the local toolchain supplies npm 12. This was found while validating #649, but the failing parser in scripts/test-init-example.ts is unchanged from main. The same complete fixture passes with npm 11.20.0, including both packed CLI distributions, scaffold installation, strict consumer types, mocked upload/delivery failures and repeat-run reuse.

Reproduction and evidence

On framework1 with the configured Node SDK checkout:

• corepack yarn exec npm --version reports 12.2.1.
• corepack yarn test:init:fixture fails with TypeError: object is not iterable at scripts/test-init-example.ts:25, where the first npm pack --json result is destructured as an array.
• corepack yarn exec npm pack ./packages/node --ignore-scripts --json --dry-run returns an object keyed by @transloadit/node.
• Running the identical fixture with Node 26.12.0 and npm 11.20.0 inherited from the host PATH passes. npm 11 returns an array of pack results.
• scripts/fingerprint-pack.ts already handles npm 12's keyed result shape. Reuse or extract its parsing approach rather than adding a separate incompatible interpretation.

No production credentials, uploads or publication were used. A temporary local stack diagnostic was removed after identifying the exact failing line. This is tooling compatibility, not a demonstrated mixed-media SDK runtime regression.

Acceptance

• The initializer fixture reads the supported array and package-name-keyed npm pack outputs and rejects missing/ambiguous package metadata clearly.
• All three package results in the fixture (Node, Utils and legacy CLI) use the same parser.
• Behavioral tests cover both JSON shapes, and the packed onboarding fixture passes with npm 11 and 12.
• Keep any shared helper limited to the actual script consumers; no SDK runtime API or dependency changes are required.

Related: #649. No implementation is being claimed by this report.

_{🤖 Released by kvz on studio1/api2-clone-8, framework1/node-sdk since 2026-11-11 · resume: codex resume 019fa2ee-f994-79d0-9d50-071bf2cb7ad6}