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>

tests/test_playoff_cache.py

@@ -1,4 +1,3 @@
-import json
 import time
 from datetime import datetime
 from zoneinfo import ZoneInfo
@@ -29,6 +28,7 @@ class _Resp:
     def raise_for_status(self):
         if self.status_code >= 400:
             import requests
+
             raise requests.HTTPError(f"HTTP {self.status_code}")
 
 
@@ -65,8 +65,10 @@ class TestBracket:
 
     def test_refresh_failure_returns_none(self, tmp_db, monkeypatch):
         import requests
+
         def raiser(*a, **kw):
             raise requests.ConnectionError("boom")
+
         monkeypatch.setattr("app.playoff_cache.requests.get", raiser)
         assert playoff_cache.refresh_bracket(2026) is None
 
@@ -94,12 +96,14 @@ class TestFetchSeries:
 
         def should_not_be_called(*a, **kw):
             raise AssertionError("network should not be called within TTL")
+
         monkeypatch.setattr("app.playoff_cache.requests.get", should_not_be_called)
 
         assert playoff_cache.fetch_series("2026-A") == payload_cached
 
     def test_stale_cache_falls_back_on_failure(self, tmp_db, monkeypatch):
         import requests
+
         key = playoff_cache.series_key("20252026", "A")
         playoff_cache._put(key, {"from": "stale"})
 
@@ -114,12 +118,14 @@ class TestFetchSeries:
 
         def raiser(*a, **kw):
             raise requests.ConnectionError("network gone")
+
         monkeypatch.setattr("app.playoff_cache.requests.get", raiser)
 
         assert playoff_cache.fetch_series("2026-A") == {"from": "stale"}
 
     def test_ancient_stale_cache_returns_none(self, tmp_db, monkeypatch):
         import requests
+
         key = playoff_cache.series_key("20252026", "A")
         playoff_cache._put(key, {"from": "ancient"})
 
@@ -146,9 +152,7 @@ class TestRecordStartDate:
 
     def test_records_on_first_playoff_sighting(self, tmp_db):
         now = datetime(2026, 4, 18, 20, 0, tzinfo=EASTERN)
-        result = playoff_cache.record_start_date_if_missing(
-            [{"gameType": 3}], now=now
-        )
+        result = playoff_cache.record_start_date_if_missing([{"gameType": 3}], now=now)
         assert result == "2026-04-18"
         assert playoff_cache.get_playoff_start_date().isoformat() == "2026-04-18"