Raise loudly when RdSAP Summary fetch returns an HTTP error 🟩

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/pashub_fetcher/pashub_client.py

@@ -140,6 +140,8 @@ class PashubClient:
         if r.status_code == 401:
             raise UnauthorizedError("Token expired or invalid")
 
+        r.raise_for_status()
+
         data: Dict[str, Any] = r.json()
         return RdSapSummary(
             pre_sap_rating=data.get("preSapRating"),