Adventure news: fix posting gates, digest counts, and section gating

- Don't post adventure beats when posting.enabled=false (PostNow ignores the flag)
- Keep the adventure channel out of the round-robin rotation so it can't steal bulletins from the digest
- no_push now retires a fact against the digest, not just the live post
- Default a missing occurred_at to now instead of the Unix epoch
- Keep protocol-relative image URLs on the guarded thumbnailer
- Make digest_hour=0 (midnight UTC) settable
- Quote the true window total in the digest, not the truncated slice
- Hide the Adventure section entirely when it's disabled

internal/storage/queries.go

@@ -256,29 +256,37 @@ func GetNewestPostableStoryByChannel(channel string) (*Story, error) {
 // that have never been posted to Matrix (no post_log row). PRIORITY beats post
 // live and so carry a post_log row; the ones left are exactly the BULLETINs the
 // daily digest collects. Oldest first so the digest reads chronologically.
-func UnpostedAdventureSince(since int64, limit int) ([]Story, error) {
-	rows, err := Get().Query(
-		`SELECT guid, headline, lede, article_url, seen_at
-		 FROM stories
-		 WHERE classified = 1
+//
+// At most `limit` rows come back, but total is how many match in all — the digest
+// quotes it to readers, so it must count the window rather than the returned page.
+func UnpostedAdventureSince(since int64, limit int) (stories []Story, total int, err error) {
+	const where = `WHERE classified = 1
 		   AND channel = 'adventure'
 		   AND seen_at >= ?
-		   AND guid NOT IN (SELECT guid FROM post_log)
+		   AND guid NOT IN (SELECT guid FROM post_log)`
+
+	if err := Get().QueryRow(`SELECT COUNT(*) FROM stories `+where, since).Scan(&total); err != nil {
+		return nil, 0, err
+	}
+
+	rows, err := Get().Query(
+		`SELECT guid, headline, lede, article_url, seen_at
+		 FROM stories `+where+`
 		 ORDER BY seen_at ASC
 		 LIMIT ?`, since, limit)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 	defer rows.Close()
 	var out []Story
 	for rows.Next() {
 		var s Story
 		if err := rows.Scan(&s.GUID, &s.Headline, &s.Lede, &s.ArticleURL, &s.SeenAt); err != nil {
-			return nil, err
+			return nil, 0, err
 		}
 		out = append(out, s)
 	}
-	return out, rows.Err()
+	return out, total, rows.Err()
 }
 
 // MarkAdventureDigested records each bulletin guid as posted (in a shared digest