feat(library): ignore a release (do-not-monitor)

Add MonitoredRelease.ignored (migration add_release_ignored). The monitor's
enqueue_due skips ignored releases, and they drop off the Wanted list —
independent of `monitored`, so auto-monitor-future can't silently re-grab
an album the user chose to ignore.

- Worker enqueue_due: AND NOT mr.ignored.
- /api/releases/[id] PATCH now accepts `ignored`; /api/wanted filters it out;
  artist detail exposes `ignored`.
- UI: Ignore button on Wanted rows; discography shows an "Ignored" badge with
  an Ignore/Un-ignore toggle (monitor + search disabled while ignored).

Worker + web tests added.

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

worker/tests/test_monitor_enqueue.py

@@ -38,6 +38,15 @@ def test_skips_unmonitored_and_fulfilled(conn):
     assert enqueue_due(conn, CFG) == 0
 
 
+def test_skips_ignored_release(conn):
+    rel_id = insert_monitored_release(conn, rg_mbid="rg-ig", monitored=True, state="wanted")
+    with conn.cursor() as cur:
+        cur.execute('UPDATE "MonitoredRelease" SET ignored = true WHERE id = %s', (rel_id,))
+    conn.commit()
+    assert enqueue_due(conn, CFG) == 0  # ignored → never enqueued even though monitored+wanted
+    assert _job_count_for(conn, rel_id) == 0
+
+
 def test_skips_when_recently_searched(conn):
     insert_monitored_release(conn, rg_mbid="rg-1", monitored=True, state="wanted",
                              last_searched_sql="now() - interval '1 hour'")  # < 6h retry