Auto-deny feeds that are not RSS or Atom type

Feeds with type other than 'rss' or 'atom' (e.g., 'unknown') are now
automatically denied on discovery. Also updated 164 existing feeds.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

feed.go

@@ -178,11 +178,13 @@ type Feed struct {
 // saveFeed stores a feed in PostgreSQL
 func (c *Crawler) saveFeed(feed *Feed) error {
 	// Default publishStatus to "held" if not set
-	// Auto-deny feeds with no language specified
+	// Auto-deny feeds with no language or non-RSS/Atom type
 	publishStatus := feed.PublishStatus
 	if publishStatus == "" {
 		if feed.Language == "" {
 			publishStatus = "deny"
+		} else if feed.Type != "rss" && feed.Type != "atom" {
+			publishStatus = "deny"
 		} else {
 			publishStatus = "held"
 		}