fix: auto-fix code issues (cron)

- 修复隐式 Optional 类型注解 (RUF013)
- 修复不必要的赋值后返回 (RET504)
- 优化列表推导式 (PERF401)
- 修复未使用的参数 (ARG002)
- 清理重复导入
- 优化异常处理

backend/subscription_manager.py

@@ -588,7 +588,8 @@ class SubscriptionManager:
         try:
             cursor = conn.cursor()
             cursor.execute(
-                "SELECT * FROM subscription_plans WHERE tier = ? AND is_active = 1", (tier,),
+                "SELECT * FROM subscription_plans WHERE tier = ? AND is_active = 1",
+                (tier,),
             )
             row = cursor.fetchone()
 
@@ -963,7 +964,9 @@ class SubscriptionManager:
             conn.close()
 
     def cancel_subscription(
-        self, subscription_id: str, at_period_end: bool = True,
+        self,
+        subscription_id: str,
+        at_period_end: bool = True,
     ) -> Subscription | None:
         """取消订阅"""
         conn = self._get_connection()
@@ -1017,7 +1020,10 @@ class SubscriptionManager:
             conn.close()
 
     def change_plan(
-        self, subscription_id: str, new_plan_id: str, prorate: bool = True,
+        self,
+        subscription_id: str,
+        new_plan_id: str,
+        prorate: bool = True,
     ) -> Subscription | None:
         """更改订阅计划"""
         conn = self._get_connection()
@@ -1125,7 +1131,10 @@ class SubscriptionManager:
             conn.close()
 
     def get_usage_summary(
-        self, tenant_id: str, start_date: datetime | None = None, end_date: datetime | None = None,
+        self,
+        tenant_id: str,
+        start_date: datetime | None = None,
+        end_date: datetime | None = None,
     ) -> dict[str, Any]:
         """获取用量汇总"""
         conn = self._get_connection()
@@ -1268,7 +1277,9 @@ class SubscriptionManager:
             conn.close()
 
     def confirm_payment(
-        self, payment_id: str, provider_payment_id: str | None = None,
+        self,
+        payment_id: str,
+        provider_payment_id: str | None = None,
     ) -> Payment | None:
         """确认支付完成"""
         conn = self._get_connection()
@@ -1361,7 +1372,11 @@ class SubscriptionManager:
             conn.close()
 
     def list_payments(
-        self, tenant_id: str, status: str | None = None, limit: int = 100, offset: int = 0,
+        self,
+        tenant_id: str,
+        status: str | None = None,
+        limit: int = 100,
+        offset: int = 0,
     ) -> list[Payment]:
         """列出支付记录"""
         conn = self._get_connection()
@@ -1501,7 +1516,11 @@ class SubscriptionManager:
             conn.close()
 
     def list_invoices(
-        self, tenant_id: str, status: str | None = None, limit: int = 100, offset: int = 0,
+        self,
+        tenant_id: str,
+        status: str | None = None,
+        limit: int = 100,
+        offset: int = 0,
     ) -> list[Invoice]:
         """列出发票"""
         conn = self._get_connection()
@@ -1581,7 +1600,12 @@ class SubscriptionManager:
     # ==================== 退款管理 ====================
 
     def request_refund(
-        self, tenant_id: str, payment_id: str, amount: float, reason: str, requested_by: str,
+        self,
+        tenant_id: str,
+        payment_id: str,
+        amount: float,
+        reason: str,
+        requested_by: str,
     ) -> Refund:
         """申请退款"""
         conn = self._get_connection()
@@ -1690,7 +1714,9 @@ class SubscriptionManager:
             conn.close()
 
     def complete_refund(
-        self, refund_id: str, provider_refund_id: str | None = None,
+        self,
+        refund_id: str,
+        provider_refund_id: str | None = None,
     ) -> Refund | None:
         """完成退款"""
         conn = self._get_connection()
@@ -1775,7 +1801,11 @@ class SubscriptionManager:
             conn.close()
 
     def list_refunds(
-        self, tenant_id: str, status: str | None = None, limit: int = 100, offset: int = 0,
+        self,
+        tenant_id: str,
+        status: str | None = None,
+        limit: int = 100,
+        offset: int = 0,
     ) -> list[Refund]:
         """列出退款记录"""
         conn = self._get_connection()
@@ -1902,7 +1932,10 @@ class SubscriptionManager:
         }
 
     def create_alipay_order(
-        self, tenant_id: str, plan_id: str, billing_cycle: str = "monthly",
+        self,
+        tenant_id: str,
+        plan_id: str,
+        billing_cycle: str = "monthly",
     ) -> dict[str, Any]:
         """创建支付宝订单（占位实现）"""
         # 这里应该集成支付宝 SDK
@@ -1919,7 +1952,10 @@ class SubscriptionManager:
         }
 
     def create_wechat_order(
-        self, tenant_id: str, plan_id: str, billing_cycle: str = "monthly",
+        self,
+        tenant_id: str,
+        plan_id: str,
+        billing_cycle: str = "monthly",
     ) -> dict[str, Any]:
         """创建微信支付订单（占位实现）"""
         # 这里应该集成微信支付 SDK