fix: long name problem fixed in chart

postgre_mcp_server.py

@@ -630,6 +630,10 @@ async def visualize_results(json_data: dict, vis_prompt: str) -> str:
 
         # Convert JSON to DataFrame
         df = pd.DataFrame(json_data["data"], columns=json_data["columns"])
+        
+        # Shorten long values in text columns
+        for column in df.select_dtypes(include=['object']).columns:
+            df[column] = df[column].apply(lambda x: str(x)[:20] + '...' if len(str(x)) > 20 else str(x))
 
         # Initialize PandasAI
         df_ai = pai.DataFrame(df)