Existing PostAttachments that are actually archives (filed opaquely before the
magic-byte gate) need extracting retroactively. cleanup_service.
reextract_archive_attachments scans PostAttachments, magic-detects the archives,
and for each reconstructs the post's sidecar from the DB + re-runs attach_in_place
in a temp dir — so the members extract and re-link to the SAME post via
find_or_create_post (source_id + external_post_id). Idempotent (members dedupe by
sha256). Enqueues thumbnail+ML for new members.
Wired as a maintenance-queue Celery task (tasks/admin) + POST
/api/admin/maintenance/reextract-archives (202) + a "Re-extract archive
attachments" card in Settings → Maintenance.
Test: a zip stored under a mangled extension-less name extracts + links its
member to the post via ImageProvenance, and a second run is a no-op (idempotent).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
bvandeusen