feat: add batch SQL execution support for MCP (#70)

* feat: add batch SQL execution support for MCP

- Add sql field to QueryResult to track executed query
- Implement execute_batch_sqls_for_mcp for executing multiple SQL
- Use sqlparse to split and execute multiple SQL in single request
- Improve error handling in execute_batch_queries
- Return multiple results format when batch queries are detected

* test: add multi-SQL statements test for query executor

doris_mcp_server/utils/db.py

@@ -59,6 +59,7 @@ class QueryResult:
     metadata: dict[str, Any]
     execution_time: float
     row_count: int
+    sql: str
 
 
 class DorisConnection:
@@ -132,6 +133,7 @@ class DorisConnection:
                     metadata=metadata,
                     execution_time=execution_time,
                     row_count=row_count,
+                    sql=sql
                 )
 
         except Exception as e: