news: close the remaining no-paywall bypass paths (Codex audit)

queries.feed was the main chokepoint, but several discovery paths have their own
SQL. Apply the shared source exclusion to all of them so "no paywalls" is truly
site-wide:
- briefs.build_daily_brief: EXCLUDE paywalled candidates (was: demote) — never
  stored in a new brief.
- queries.brief: stored-brief retrieval (covers /today + /api/brief) filters the
  paywalled source.
- digest.digest_items + followed_digest_items: the morning email + "from what you
  follow" omit paywalled sources.
- sitemap(): paywalled article pages excluded from the sitemap.
All reuse queries.paywalled_source_ids (admin override still wins).

Regression tests (test_paywall_exclusion.py): never stored in a new brief; /today
+ digest omit it; followed-source email omits it; Saved retains it; 'free'
override restores eligibility. 423 backend tests green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

goodnews/digest.py

@@ -17,6 +17,7 @@ from html import escape
 from . import email_send
 from .localtime import local_now, local_today
 from .paywall import is_paywalled, is_paywalled_for_source
+from .queries import paywalled_source_ids
 
 DIGEST_HOUR = int(os.environ.get("GOODNEWS_DIGEST_HOUR", "7"))
 DIGEST_WINDOW_HOURS = 4  # send between DIGEST_HOUR and +4h, site-local
@@ -29,8 +30,10 @@ def _base_url() -> str:
 
 def digest_items(conn: sqlite3.Connection, brief_date: str, limit: int = 7) -> list[dict]:
     """The brief's items with the bits a calm email needs (visible sources only)."""
+    pwx = paywalled_source_ids(conn)
+    pw_clause = f" AND a.source_id NOT IN ({','.join('?' * len(pwx))})" if pwx else ""
     rows = conn.execute(
-        """
+        f"""
         SELECT a.id, a.title, a.canonical_url, s.name AS source, s.paywall_override, sc.reason_text,
                (SELECT summary FROM article_summaries WHERE article_id = a.id) AS summary
         FROM daily_briefs b
@@ -38,11 +41,11 @@ def digest_items(conn: sqlite3.Connection, brief_date: str, limit: int = 7) -> l
         JOIN articles a ON a.id = bi.article_id
         JOIN sources s ON s.id = a.source_id
         LEFT JOIN article_scores sc ON sc.article_id = a.id
-        WHERE b.brief_date = ? AND s.content_visible = 1
+        WHERE b.brief_date = ? AND s.content_visible = 1{pw_clause}
         ORDER BY bi.rank
         LIMIT ?
         """,
-        (brief_date, limit),
+        (brief_date, *pwx, limit),
     ).fetchall()
     items = []
     for r in rows:
@@ -72,6 +75,8 @@ def followed_digest_items(conn: sqlite3.Connection, user_id: int, exclude_ids, l
             f"AND at.tag IN ({','.join('?' * len(ftags))}))"
         )
         params += ftags
+    pwx = paywalled_source_ids(conn)
+    pw_clause = f" AND a.source_id NOT IN ({','.join('?' * len(pwx))})" if pwx else ""
     rows = conn.execute(
         f"""
         SELECT a.id, a.title, a.canonical_url, s.name AS source, s.paywall_override, a.source_id, sc.reason_text,
@@ -79,12 +84,12 @@ def followed_digest_items(conn: sqlite3.Connection, user_id: int, exclude_ids, l
         FROM articles a
         JOIN sources s ON s.id = a.source_id
         JOIN article_scores sc ON sc.article_id = a.id
-        WHERE sc.accepted = 1 AND a.duplicate_of IS NULL AND s.content_visible = 1
+        WHERE sc.accepted = 1 AND a.duplicate_of IS NULL AND s.content_visible = 1{pw_clause}
           AND ({' OR '.join(ors)})
         ORDER BY COALESCE(a.published_at, a.discovered_at) DESC
         LIMIT 30
         """,
-        params,
+        [*pwx, *params],
     ).fetchall()
     exclude, per_source, out = set(exclude_ids), {}, []
     for r in rows: