check for doubles

uploader.py

@@ -172,6 +172,9 @@ def fetch_all_books(cfg: CalibreConfig) -> list[dict]:
         )
         resp.raise_for_status()
         data = resp.json()
+        if start == 0:
+            non_list = {k: v for k, v in data.items() if not isinstance(v, list)}
+            log.info("listbooks page-0 meta fields: %s", non_list)
         # Calibre-Web uses DataTables format: "data"/"recordsTotal", older versions use "rows"/"total_count"
         rows = data.get("rows") or data.get("data") or []
         total = (