style: apply ruff format and fix lint issues in playoff modules

- Rename single-letter `l` loop variables in bracket_view to satisfy E741
- Drop unused `json` import from test_playoff_cache (F401/F811)

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

app/playoff_cache.py

@@ -21,8 +21,8 @@ logger = logging.getLogger(__name__)
 
 EASTERN = ZoneInfo("America/New_York")
 
-BRACKET_TTL = 3600       # refresh at this cadence via scheduler
-SERIES_TTL = 300          # lazy cache for per-series schedule fetches
+BRACKET_TTL = 3600  # refresh at this cadence via scheduler
+SERIES_TTL = 300  # lazy cache for per-series schedule fetches
 MAX_STALE_SECONDS = 86400  # 24h
 
 SERIES_ID_RE = re.compile(r"^(20\d{2})-([A-P])$")
@@ -78,6 +78,7 @@ def _get(cache_key):
 
 # ── Bracket ────────────────────────────────────────────────────────
 
+
 def bracket_key(year):
     return f"bracket:{year}"
 
@@ -109,6 +110,7 @@ def get_bracket(year=None):
 
 # ── Per-series schedule ────────────────────────────────────────────
 
+
 def series_key(season, letter):
     return f"series:{season}:{letter.upper()}"
 
@@ -140,7 +142,9 @@ def fetch_series(series_id):
         if time.time() - fetched < SERIES_TTL:
             return payload
 
-    url = f"https://api-web.nhle.com/v1/schedule/playoff-series/{season}/{letter.lower()}"
+    url = (
+        f"https://api-web.nhle.com/v1/schedule/playoff-series/{season}/{letter.lower()}"
+    )
     try:
         resp = requests.get(url, timeout=10)
         resp.raise_for_status()
@@ -189,7 +193,9 @@ def record_start_date_if_missing(scoreboard_games, now=None):
 
     now = now or datetime.now(EASTERN)
     today = now.date().isoformat()
-    _put(META_KEY, {"first_date": today, "recorded_at_utc": now.astimezone().isoformat()})
+    _put(
+        META_KEY, {"first_date": today, "recorded_at_utc": now.astimezone().isoformat()}
+    )
     return today