library.importPreview scans/probes (probes reused by the import) and marks duplicates;
library.import gains preset, keywords and albumName and is one undo step; File > Add Photos
opens a review grid (thumbnails, checkboxes, duplicates unchecked), add in place or copy into
the dated Originals folders, batched import with progress; engine + headless tests.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>