fix: show correct "Game X of 7" for future playoff dates

Enrich raw score-endpoint games with gameNumber from the series cache
before parsing. The score API omits gameNumber and its seriesStatus
reflects current wins, so all future games in a series computed the
same number. Now we cross-reference by game id against the cached
series-detail endpoint which includes the correct gameNumber per game.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_playoff_series.py

@@ -181,9 +181,15 @@ class TestSeriesSummary:
         )
         assert series_summary(game) == "Game 2 of 7"
 
-    def test_fut_game_suppresses_summary(self):
+    def test_fut_game_uses_explicit_game_number(self):
+        game = make_playoff_game(
+            top_wins=1, bottom_wins=1, game_state="FUT", game_number=4
+        )
+        assert series_summary(game) == "Game 4 of 7"
+
+    def test_fut_game_without_game_number_uses_fallback(self):
         game = make_playoff_game(top_wins=1, bottom_wins=1, game_state="FUT")
-        assert series_summary(game) == ""
+        assert series_summary(game) == "Game 3 of 7"
 
 
 class TestIsPinned: