The CLI fallback carried the defect #1129 fixed in the admin route: it computed `storage/events/active/<photo.path>` and fs.access'd it, a location that does not exist for external or reference rows. Every one failed the check and was counted as an error, so on an external-media install the script was inert while reporting one error per photo.
Resolution now goes through ensureThumbnail, which already branches on source_origin and owns the per-photo ext<id>_ output name — sharing it is what stops the script and the route drifting apart again.
Also: videos skipped on every marker they can carry (fileWatcher writes type and mime_type but never media_type), responsive tiers backfilled alongside the canonical rendition, skip-vs-generate asked from isThumbnailValid rather than inferred from an unchanged path, tier failures counted rather than swallowed, and a nonzero exit when the backfill was incomplete.
The script is now importable with the CLI behind a require.main guard; it previously ran on require and called process.exit, so it could not be tested at all — which is why this survived #1129.
Merged with admin privileges: the author cannot self-approve.
Paul Nothaft
b581267031