feat: 实现受控真实下单安全边界 (#99)

client/src/pdd_purchase_adapter.py

@@ -21,6 +21,8 @@ class PurchasePageState:
     quantity: int = 0
     price_cent: int = 0
     candidate_count: int = 1
+    in_stock: bool = True
+    submit_candidate_count: int = 0
 
 
 class PddPurchaseError(RuntimeError):
@@ -73,3 +75,11 @@ class PddPurchaseAdapter(ABC):
     @abstractmethod
     def close(self) -> None:
         """释放设备会话；不得在此方法中产生页面点击。"""
+
+
+class PddLivePurchaseAdapter(PddPurchaseAdapter):
+    """受控真实采购接口；只增加一次性提交，不提供付款或取消。"""
+
+    @abstractmethod
+    def submit_order_once(self) -> None:
+        """用最新页面状态确认唯一按钮并单击一次；调用后禁止重试。"""