refactor: centralize numeric normalization

app/backend/features/market/insights.py

@@ -6,6 +6,7 @@ from datetime import datetime, time as dt_time, timedelta, timezone
 from statistics import median
 from typing import TYPE_CHECKING, Any, Callable
 
+from backend.data.numbers import non_nan_number as _number
 from backend.data.providers.ifind_client import IfindError, IfindHttpClient
 from backend.data.providers.tushare_client import TushareClient, TushareError
 
@@ -16,14 +17,6 @@ if TYPE_CHECKING:
 CHINA_TIMEZONE = timezone(timedelta(hours=8))
 
 
-def _number(value: Any, default: float = 0.0) -> float:
-    try:
-        number = float(value)
-        return number if number == number else default
-    except (TypeError, ValueError):
-        return default
-
-
 def _display_date(value: str) -> str:
     text = str(value or "").replace("-", "")
     if len(text) != 8: