feat: make scoreboard playoff-aware with banner, bracket, and series drill-down

Turn a regular-season-looking Tuesday into a full playoff experience:

- Playoff banner with round + day + series + elimination counts, gold/silver
  Cup theme toggled by body.playoff-mode
- Series context on each playoff card: round chip, series score, stake badges
  (GAME 7, CLINCHER, PIVOTAL), and one-line blurb
- Game 7s pin to a new Spotlight section above Live
- Playoff OT renders with SUDDEN DEATH badge and pulsing gold border
- Client-side OT notifications via bell button in the banner
- New /series/<id> drill-down with headline, next-game, and game-by-game history
- New /bracket page: 7-column desktop grid, accordion on mobile
- Day N banner count auto-anchors on first playoff scoreboard hit
- SQLite cache for bracket + per-series schedules, stale-on-failure up to 24h

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_scheduler.py

@@ -6,6 +6,7 @@ from app.scheduler import start_scheduler
 class TestStartScheduler:
     def test_registers_standings_refresh_every_600_seconds(self, mocker):
         mock_schedule = mocker.patch("app.scheduler.schedule")
+        mocker.patch("app.scheduler.refresh_bracket")
         mocker.patch("app.scheduler.time.sleep", side_effect=StopIteration)
 
         with pytest.raises(StopIteration):
@@ -16,6 +17,7 @@ class TestStartScheduler:
 
     def test_registers_score_refresh_every_10_seconds(self, mocker):
         mock_schedule = mocker.patch("app.scheduler.schedule")
+        mocker.patch("app.scheduler.refresh_bracket")
         mocker.patch("app.scheduler.time.sleep", side_effect=StopIteration)
 
         with pytest.raises(StopIteration):
@@ -24,8 +26,30 @@ class TestStartScheduler:
         intervals = [call[0][0] for call in mock_schedule.every.call_args_list]
         assert 10 in intervals
 
+    def test_registers_bracket_refresh_every_3600_seconds(self, mocker):
+        mock_schedule = mocker.patch("app.scheduler.schedule")
+        mocker.patch("app.scheduler.refresh_bracket")
+        mocker.patch("app.scheduler.time.sleep", side_effect=StopIteration)
+
+        with pytest.raises(StopIteration):
+            start_scheduler()
+
+        intervals = [call[0][0] for call in mock_schedule.every.call_args_list]
+        assert 3600 in intervals
+
+    def test_invokes_bracket_refresh_eagerly_at_startup(self, mocker):
+        mocker.patch("app.scheduler.schedule")
+        eager = mocker.patch("app.scheduler.refresh_bracket")
+        mocker.patch("app.scheduler.time.sleep", side_effect=StopIteration)
+
+        with pytest.raises(StopIteration):
+            start_scheduler()
+
+        assert eager.called
+
     def test_runs_pending_on_each_tick(self, mocker):
         mock_schedule = mocker.patch("app.scheduler.schedule")
+        mocker.patch("app.scheduler.refresh_bracket")
         call_count = {"n": 0}
 
         def sleep_twice(_):
@@ -42,6 +66,7 @@ class TestStartScheduler:
 
     def test_continues_after_exception_in_run_pending(self, mocker):
         mock_schedule = mocker.patch("app.scheduler.schedule")
+        mocker.patch("app.scheduler.refresh_bracket")
         call_count = {"n": 0}
 
         def raise_then_stop(_):