fix: add detector mock to pipeline test fixture

The persist_assessments feature accesses settings.detector which the
existing mock_settings fixture didn't include.

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

tests/test_pipeline.py

@@ -44,6 +44,9 @@ def mock_settings():
     telegram.bot_token = None
     telegram.chat_id = None
 
+    detector = MagicMock()
+    detector.persist_assessments = False
+
     settings = MagicMock(spec=Settings)
     settings.redis = redis
     settings.database = database
@@ -51,6 +54,7 @@ def mock_settings():
     settings.polymarket = polymarket
     settings.discord = discord
     settings.telegram = telegram
+    settings.detector = detector
     settings.dry_run = True
     return settings