feat(polymarket): exclude sports markets before category detection

Add _SPORTS_EXCLUSIONS list checked first in _detect_category so NBA/NFL/
MLB/NHL/tennis/golf/UFC/boxing/wrestling/tournament markets never bleed into
politics or events categories. Also removes 'super bowl' from _EVENTS_KEYWORDS
since it's now covered by the sports exclusion.

Keywords excluded: nba, nfl, mlb, nhl, basketball, football, baseball, hockey,
soccer, mvp, rookie of the, championship, super bowl, world series, playoffs,
playoff, tournament, tennis, golf, ufc, boxing, wrestler, wrestling,
slam dunk, home run, touchdown.

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

bot/data/polymarket.py

@@ -82,9 +82,25 @@ class PolymarketClient:
     ]
 
     _EVENTS_KEYWORDS: list[str] = [
-        "super bowl", "world cup", "oscar", "nobel", "spacex", "nasa",
+        "world cup", "oscar", "nobel", "spacex", "nasa",
     ]
 
+    # Sports markets are excluded entirely — BTC/F&G/GNews have no edge there.
+    # Checked before any category match so sports don't bleed into politics/events.
+    _SPORTS_EXCLUSIONS: list[str] = [
+        " nba ", " nfl ", " mlb ", " nhl ",
+        "basketball", "football", "baseball", "hockey", "soccer",
+        " mvp ", "rookie of the", "championship", "super bowl", "world series",
+        "playoffs", "playoff", "tournament",
+        "tennis", " golf ", " ufc ", "boxing", "wrestler", "wrestling",
+        "slam dunk", "home run", "touchdown",
+    ]
+
+    @classmethod
+    def _is_sports(cls, question: str) -> bool:
+        q = f" {question.lower()} "
+        return any(kw in q for kw in cls._SPORTS_EXCLUSIONS)
+
     @classmethod
     def _is_crypto_finance(cls, question: str) -> bool:
         q = f" {question.lower()} "  # pad so edge keywords match cleanly
@@ -108,6 +124,8 @@ class PolymarketClient:
     @classmethod
     def _detect_category(cls, question: str) -> str:
         """Return the category label for a market question, or '' if unsupported."""
+        if cls._is_sports(question):
+            return ""  # exclude sports regardless of other keyword matches
         if cls._is_crypto_finance(question):
             return "crypto/finance"
         if cls._is_politics(question):