Keep the publication an article's page declares

Readability already reads og:site_name and JSON-LD publisher.name; carry
that through Page and Extracted and store it in articles.publication, the
same way the page byline is kept. `publication_label` is what the readers
will see after the feed name: the site name, else the domain, and nothing
when it would only repeat the feed's own title.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YWmCpUojfHXhSZ2129Z7Nv

examples/image_audit.rs

@@ -358,6 +358,7 @@ fn pick_for(target: &Target, content_html: String) -> Pick {
             first_seen: "2026-08-15T05:30:00Z".parse().unwrap(),
             url: target.url.clone(),
             author: None,
+            publication: None,
             feed_id: 1,
             feed_title: host(&target.url),
             category: None,