Root cause: Google News RSS items carry no enclosures; pipeline fell back
to og:image from the news.google.com interstitial, which serves ONE shared
Google-branded tile (lh3.googleusercontent.com/J6_coFbo...) for every
article. 601 rows shared that URL (maple 243 / finance 358). New
image-guard blocks *.googleusercontent.com images at ingest; 16/16
regression tests; prod DBs migrated tile->NULL; images rebuilt
technews:10 finance:4 maple-brief:11 and deployed.