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/conftest.py

@@ -19,6 +19,8 @@ def make_game(
     game_type=2,
     situation=None,
     series_status=None,
+    home_abbrev="TOR",
+    away_abbrev="BOS",
 ):
     clock = {
         "timeRemaining": f"{seconds_remaining // 60:02d}:{seconds_remaining % 60:02d}",
@@ -33,6 +35,7 @@ def make_game(
         "clock": clock,
         "homeTeam": {
             "name": {"default": home_name},
+            "abbrev": home_abbrev,
             "score": home_score,
             "sog": 15,
             "logo": "https://example.com/home.png",
@@ -40,6 +43,7 @@ def make_game(
         },
         "awayTeam": {
             "name": {"default": away_name},
+            "abbrev": away_abbrev,
             "score": away_score,
             "sog": 12,
             "logo": "https://example.com/away.png",
@@ -52,6 +56,49 @@ def make_game(
     }
 
 
+def make_playoff_game(
+    top_wins=0,
+    bottom_wins=0,
+    round_num=1,
+    series_letter="A",
+    top_abbrev="TOR",
+    bottom_abbrev="BOS",
+    top_is_home=True,
+    game_state="LIVE",
+    **kwargs,
+):
+    """Convenience wrapper around make_game for playoff fixtures.
+
+    `top_is_home` controls which side of the matchup hosts this game, so tests
+    for the blurb copy (leader vs. trailer names) don't have to juggle raw dicts.
+    """
+    series_status = {
+        "round": round_num,
+        "topSeedWins": top_wins,
+        "bottomSeedWins": bottom_wins,
+        "seriesLetter": series_letter,
+        "topSeedTeamAbbrev": top_abbrev,
+        "bottomSeedTeamAbbrev": bottom_abbrev,
+    }
+    if top_is_home:
+        home_abbrev, away_abbrev = top_abbrev, bottom_abbrev
+        home_name, away_name = "Top Seeds", "Bottom Seeds"
+    else:
+        home_abbrev, away_abbrev = bottom_abbrev, top_abbrev
+        home_name, away_name = "Bottom Seeds", "Top Seeds"
+
+    return make_game(
+        game_state=game_state,
+        game_type=3,
+        series_status=series_status,
+        home_abbrev=kwargs.pop("home_abbrev", home_abbrev),
+        away_abbrev=kwargs.pop("away_abbrev", away_abbrev),
+        home_name=kwargs.pop("home_name", home_name),
+        away_name=kwargs.pop("away_name", away_name),
+        **kwargs,
+    )
+
+
 LIVE_GAME = make_game()
 PRE_GAME = make_game(
     game_state="FUT", home_score=0, away_score=0, period=0, seconds_remaining=1200
@@ -89,9 +136,11 @@ def flask_client(tmp_path, monkeypatch):
     # Patch module-level path constants so no reloads are needed
     import app.routes as routes
     import app.games as games
+    import app.playoff_cache as playoff_cache
 
     monkeypatch.setattr(routes, "SCOREBOARD_DATA_FILE", str(scoreboard_file))
     monkeypatch.setattr(games, "DB_PATH", str(db_path))
+    monkeypatch.setattr(playoff_cache, "DB_PATH", str(db_path))
 
     from app import app as flask_app