Add interval-aware polling and a 'cycle' command for scheduling

- poll_due_sources(): polls only sources whose last successful poll is older
  than their poll_interval_minutes (or never polled), finally giving that
  config field meaning.
- classify gains only_unclassified to spend the LLM solely on new (heuristic)
  articles, so a frequent scheduled run stays cheap.
- 'cycle' command runs poll-due -> classify-new -> rebuild-today's-brief, with
  each step non-fatal so a down model endpoint or empty day never aborts it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

goodnews/feeds.py

@@ -28,13 +28,40 @@ class FeedItem:
 
 
 def poll_all_sources(conn: sqlite3.Connection, limit: int | None = None) -> dict:
-    query = """
-        SELECT *
-        FROM sources
-        WHERE active = 1
-        ORDER BY id
+    return _poll_rows(conn, conn.execute(
+        "SELECT * FROM sources WHERE active = 1 ORDER BY id"
+    ).fetchall(), limit)
+
+
+def poll_due_sources(conn: sqlite3.Connection, limit: int | None = None) -> dict:
+    """Poll only active sources whose last successful poll is older than their
+    poll_interval_minutes (or that have never been polled successfully).
+
+    This is what makes poll_interval_minutes meaningful and lets a scheduler run
+    frequently without re-hitting feeds that are not yet due.
     """
-    rows = conn.execute(query).fetchall()
+    rows = conn.execute(
+        """
+        SELECT s.*
+        FROM sources s
+        WHERE s.active = 1
+          AND (
+            NOT EXISTS (
+                SELECT 1 FROM ingest_runs r
+                WHERE r.source_id = s.id AND r.status = 'ok'
+            )
+            OR (
+                SELECT MAX(r.finished_at) FROM ingest_runs r
+                WHERE r.source_id = s.id AND r.status = 'ok'
+            ) <= datetime('now', '-' || s.poll_interval_minutes || ' minutes')
+          )
+        ORDER BY s.id
+        """
+    ).fetchall()
+    return _poll_rows(conn, rows, limit)
+
+
+def _poll_rows(conn: sqlite3.Connection, rows: list[sqlite3.Row], limit: int | None) -> dict:
     if limit is not None:
         rows = rows[:limit]