Premium Orion Datasets and the spatial backfill

Changes since 2.21.0.

#New

• Premium Orion Datasets: every statistics table Orion spatializes — joined to administrative boundaries so it can be drawn on a map — is now marked premium with derived_by = Orion Terrametrics on the record. The dataset page shows a Premium Orion Dataset badge and a Derived by row, and the description states that the derived product is owned by Orion Terrametrics while naming the original publisher. The original source stays fully attributed (publisher, licence, citation). This marker is what the future premium pricing gate will key on.
• Spatial join backfill: a new hourly spatial_plan job plans the join for statistics tables that were harvested before the spatial gate ran, or whose plan failed once (retried after 7 days). A successful plan stores the table_join access entry, coverage, columns and sample rows exactly as at harvest, and marks the record premium. A record whose plan keeps failing waits and stays unpublished rather than publishing as a bare table.
• Human titles from OrionAI: when a record's title is a file or layer name (e.g. ken_admin1, layer-3.shp), the enrichment job now asks OrionAI for a short human title from the record's facts. The rewrite is recorded in title_by = orionai; a steward's edited title is never replaced.

#Improved

• The enrichment sweep now also selects records that need a title, not only those needing a description or coverage.
• A re-harvest of an already-spatialized table keeps its premium marker and ownership sentence.