Export serializeLibraryAsJSON from the package

Editor assessment

A good follow-up fix: 'export serializeLibraryAsJSON from the package' precisely states what was missing — the earlier commit created the helper but didn't export it — in lowercase imperative style within length limits. The type is correct since the omission was a real defect for package consumers, and the patch-level inference is right. The absent scope and body are acceptable given the surgical nature of the change, though one line noting how the export was missed (re-export index update?) would round it out. No structural or footer problems; clean git log reading.