fix warning

process_kpi/kpi_health_check/engine_v2.py

@@ -289,7 +289,12 @@ def evaluate_health_check(
     if not out_frames:
         return pd.DataFrame(), pd.DataFrame()
 
-    status_df = pd.concat(out_frames, ignore_index=True)
+    # Filter out empty frames to avoid FutureWarning about empty/all-NA entries
+    non_empty_frames = [f for f in out_frames if not f.empty and not f.isna().all().all()]
+    if not non_empty_frames:
+        return pd.DataFrame(), pd.DataFrame()
+
+    status_df = pd.concat(non_empty_frames, ignore_index=True)
 
     summary = (
         status_df.groupby("site_code", as_index=False)