Adds Export / Import buttons to the Classify & Copy header so the full dataset
(tracking + transmittal trees, per-file assignments, output name) round-trips
through a JSON file — export it, edit externally (e.g. with an AI), re-import.
- Export downloads a self-documenting JSON (canonical classify.serialize() state
+ an informational sourceFiles inventory + a _format note). Lossless: empty
tree branches and unassigned state survive.
- Import validates, confirms before replacing a non-empty current dataset, and
loads via classify.load() (ignores the wrapper/_format/sourceFiles keys).
Test: serialize → JSON → load preserves trees (incl. an empty branch) +
assignments (classify.spec.js -> 34 passed).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>