Fix NaN JSON serialization in summarise_dataframe

src/data/data_providers.py

@@ -38,6 +38,7 @@ Loose coupling guarantees:
 
 from __future__ import annotations
 
+import math
 import time
 import traceback
 from abc import ABC, abstractmethod
@@ -137,7 +138,8 @@ def summarise_dataframe(df: pd.DataFrame, max_rows: int = 48) -> Dict[str, Any]:
                 if isinstance(v, (pd.Timestamp, datetime)):
                     r[k] = str(v)
                 elif isinstance(v, (float, np.floating)):
-                    r[k] = round(float(v), 2)
+                    fv = float(v)
+                    r[k] = None if (math.isnan(fv) or math.isinf(fv)) else round(fv, 2)
         return {"rows": records, "row_count": len(records)}
 
     # Summarise