Take the author from the article page, not the aggregator submitter

Readability already finds a byline (JSON-LD author, meta author tags,
byline markup); keep it on the article and let it replace an aggregator
entry's author, which for HN and friends is the submitter. A direct feed's
own author is still trusted over the page, and an aggregator name is only
used at all when no direct feed carried the story. The author is stored on
articles so it survives independently of the best entry.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QVPagF6jfDv78CC5Jv2wp4

src/types.rs

@@ -90,6 +90,8 @@ pub enum ExtractMethod {
 pub struct Extracted {
     /// Sanitized XHTML-safe body markup.
     pub content_html: String,
+    /// Author discovered in the fetched page, if any.
+    pub author: Option<String>,
     pub word_count: i64,
     /// True when we only have an excerpt/paywall stub — penalized in pre-filter.
     pub excerpt_only: bool,
@@ -119,7 +121,7 @@ pub struct Article {
     pub sources: Vec<SourceRef>,
     pub first_seen: Timestamp,
 
-    // --- denormalized, not stored on `articles` ---
+    // --- joined / derived fields ---
     pub url: String,
     pub author: Option<String>,
     pub feed_id: FeedId,