Admin Ads Claims Refresh

Recompute claimed_blocks + claimed_reach for one publisher.

For every calendar month with at least one DetectedSponsorBlock, produce a PublisherAdClaim row holding:

• claimed_blocks count of distinct detected blocks for the publisher in that month.
• claimed_reach total plays rows attached to the distinct articles those blocks belong to.

Idempotent — re-running on the same data yields identical rows. The join is done at the slug level (DetectedSponsorBlock.article_slug == Article.slug AND Article.publisher_id == publisher_id), so a publisher only ever counts plays of its own articles.