Handle query_type as both list and string in cache document analysis

Author: Robbie1977

src/vfbquery/solr_result_cache.py

@@ -427,7 +427,9 @@ def get_cache_stats(self) -> Dict[str, Any]:
 
                 # Analyze each cache document
                 for doc in docs:
-                    query_type = doc.get("query_type", "unknown")
+                    query_type_field = doc.get("query_type", "unknown")
+                    # Handle both list and string formats
+                    query_type = query_type_field[0] if isinstance(query_type_field, list) else query_type_field
                     type_stats[query_type] = type_stats.get(query_type, 0) + 1
 
                     try: