fix: ensure page2 is closed even on exception in process_single_order

Wrap the order processing logic in try-finally to guarantee cleanup
of the popup page regardless of whether processing succeeds or fails.

Co-Authored-By: Claude (glm-5) <noreply@anthropic.com>

utils/discrete_material_plan_cleaner.py

@@ -220,6 +220,7 @@ class DiscreteMaterialPlanCleaner:
         ).group(1)
 
         # 6. 执行清理逻辑
+        try:
             if detail_status == "审批通过":
                 if detail_count > 0:
                     # 更新总物料数统计
@@ -392,6 +393,7 @@ class DiscreteMaterialPlanCleaner:
                 self._log("订单已完成，无需处理")
             else:
                 self._log(f"订单状态为 [{detail_status}]，不符合处理条件", "warn")
+        finally:
             page2.close()
 
     def setup_query_interface(self, inner_frame):