fix: support npm 12 pack output

[heimanba]

Root cause

npm 12 changed npm pack --json from a one-element array to a package-name keyed object. The release smoke test rejected the new valid format after all three publish dry-runs passed.

Fix

• accept both npm 10/11 array output and npm 12 package-map output
• add regression coverage for both formats and ambiguous output

Verification

• full pre-push verification passed
• package smoke test passed using npm 12.0.1
• no package was published by the failed workflow

After merge, retry the same approval-gated stable 0.0.2 publish.