AI Recommendation Index — the category as PUBLISHED on a date

Reads the immutable archive: the rankings this Index actually published on or before the requested date, at their latest revision. This is a record, not a recomputation — the API never re-derives a historical window under current extraction rules and presents it as history. Every response discloses source ("cron" = captured live that day; "backfill" = reconstructed later from run history), the extraction_version the underlying sightings were produced under, and the revision (a correction supersedes the original for the same date and carries a correction_note). Dates before the archive begins return status "no_record" with the earliest date on file.