refactor: centralize compact date formatting

app/backend/features/screener/engine.py

@@ -8,6 +8,7 @@ from collections import defaultdict
 from datetime import datetime, timedelta
 from typing import Any
 
+from backend.bootstrap.config import display_compact_date as _display_date
 from backend.data.numbers import finite_number as _number
 from backend.data.providers.tushare_client import TushareClient, TushareError
 from backend.features.screener.strategies import ADVANCED_CURATED_STRATEGIES
@@ -2200,7 +2201,3 @@ def _regime_reason(regime: str) -> str:
         "divergence": "指数或核心仍强，但广度、封板质量开始分化。",
         "retreat": "情绪指标继续走弱，应提高筛选门槛并接受无候选结果。",
     }.get(regime, "市场阶段待确认。")
-
-
-def _display_date(value: str) -> str:
-    return f"{value[:4]}-{value[4:6]}-{value[6:8]}" if len(value) == 8 else value