[Dx-Alz-xD]

closes #545

adds scripts/remove-ghost-papers.mjs for removing the records whose pdf no longer exists in the bucket

usage, with MONGODB_URI in .env:

• npm run ghost-papers lists the ghost records and deletes nothing
• npm run ghost-papers -- --delete removes them

how it decides

• sends a HEAD request to file_url for every record in papers and admins (the upload queue), same as the viewer check from fix: Resolve bulk downloads, PostHog crash, and missing file UX #544
• only a 404 counts as missing. 403, 5xx, timeouts, unreachable hosts and records without a file_url are listed as "could not be checked" and never deleted

safety

• dry run unless --delete is passed
• before deleting it writes the full records to ghost-papers-.json (gitignored) so they can be restored
• deletes by _id and file_url together, so a record that was re-uploaded in the meantime is kept
• refuses to delete when more than half the files are missing, since a moved or renamed bucket also answers 404

tested against an in-memory mongodb and a local file server: the dry run changed nothing, --delete removed exactly the 404 records from both collections and kept the 403/500/unreachable/no-url ones, the backup had the full records, a second run found nothing, and the more-than-half guard refused with all files missing. also checked that storage.googleapis.com answers 404 for a missing object in a public bucket

notes

• --env-file needs node 20.6 or newer
• only file_url is checked, a missing thumbnail alone doesn't count