fix: stabilize production payment flow

apps/billing/payment_gateways.py

@@ -94,6 +94,25 @@ def _wechat_amount_cents(value) -> int:
     return int((_decimal_money(value) * Decimal("100")).to_integral_value())
 
 
+def _wechat_response_payload(response) -> dict:
+    if isinstance(response, dict):
+        return response
+    if isinstance(response, tuple) and len(response) >= 2:
+        payload = response[1]
+        if isinstance(payload, dict):
+            return payload
+        if isinstance(payload, bytes):
+            payload = payload.decode("utf-8")
+        if isinstance(payload, str):
+            try:
+                parsed = json.loads(payload)
+            except json.JSONDecodeError as exc:
+                raise ValueError("WeChat API response is not valid JSON.") from exc
+            if isinstance(parsed, dict):
+                return parsed
+    raise ValueError("WeChat API response has an unsupported format.")
+
+
 def _default_expires_at():
     minutes = int(getattr(settings, "PAYMENT_QR_EXPIRES_MINUTES", 10) or 10)
     return timezone.now() + timedelta(minutes=minutes)
@@ -198,7 +217,7 @@ def _create_mock_payment_order(order: RechargeOrder) -> PaymentOrderCode:
 
 def _create_wechat_payment_order_with_sdk(order: RechargeOrder) -> PaymentOrderCode:
     try:
-        from wechatpayv3 import WeChatPay  # type: ignore
+        from wechatpayv3 import WeChatPay, WeChatPayType  # type: ignore
     except ImportError as exc:
         raise PaymentOrderCreateError("wechatpayv3 is not installed.") from exc
 
@@ -231,11 +250,16 @@ def _create_wechat_payment_order_with_sdk(order: RechargeOrder) -> PaymentOrderC
                 "total": _wechat_amount_cents(order.amount_money),
                 "currency": order.currency,
             },
+            pay_type=WeChatPayType.NATIVE,
         )
     except Exception as exc:  # pragma: no cover - depends on merchant SDK/runtime.
         raise PaymentOrderCreateError("WeChat native order creation failed.") from exc
 
-    code_url = response.get("code_url") if isinstance(response, dict) else None
+    try:
+        payload = _wechat_response_payload(response)
+    except ValueError as exc:
+        raise PaymentOrderCreateError("WeChat native order response was invalid.") from exc
+    code_url = payload.get("code_url")
     if not code_url:
         raise PaymentOrderCreateError("WeChat native order did not return code_url.")
     return PaymentOrderCode(code_url=str(code_url), expires_at=_default_expires_at())
@@ -398,7 +422,7 @@ def _query_wechat_payment_order_with_sdk(order: RechargeOrder) -> RechargePaymen
             "WeChat active payment query SDK binding is not configured."
         )
     try:
-        resource = query(out_trade_no=order.order_no)
+        resource = _wechat_response_payload(query(out_trade_no=order.order_no))
     except Exception as exc:  # pragma: no cover - depends on merchant SDK/runtime.
         raise PaymentQueryUnavailableError("WeChat trade query failed.") from exc
     if resource.get("trade_state") != "SUCCESS":