refactor: centralize numeric normalization

app/backend/features/sentiment/engine.py

@@ -4,6 +4,8 @@ from copy import deepcopy
 from statistics import mean, median
 from typing import Any
 
+from backend.data.numbers import non_nan_number as _number
+
 
 COMPONENT_WEIGHTS = {
     "breadth": 20,
@@ -16,14 +18,6 @@ COMPONENT_WEIGHTS = {
 SENTIMENT_ENGINE_VERSION = 2
 
 
-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 _clamp(value: float, lower: float = 0.0, upper: float = 100.0) -> float:
     return min(upper, max(lower, value))