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/test_phase8_task1.py

@@ -29,7 +29,10 @@ def test_tenant_management() -> None:
     # 1. 创建租户
     print("\n1.1 创建租户...")
     tenant = manager.create_tenant(
-        name="Test Company", owner_id="user_001", tier="pro", description="A test company tenant",
+        name="Test Company",
+        owner_id="user_001",
+        tier="pro",
+        description="A test company tenant",
     )
     print(f"✅ 租户创建成功: {tenant.id}")
     print(f"   - 名称: {tenant.name}")
@@ -53,7 +56,9 @@ def test_tenant_management() -> None:
     # 4. 更新租户
     print("\n1.4 更新租户信息...")
     updated = manager.update_tenant(
-        tenant_id=tenant.id, name="Test Company Updated", tier="enterprise",
+        tenant_id=tenant.id,
+        name="Test Company Updated",
+        tier="enterprise",
     )
     assert updated is not None, "更新租户失败"
     print(f"✅ 租户更新成功: {updated.name}, 层级: {updated.tier}")
@@ -163,7 +168,10 @@ def test_member_management(tenant_id: str) -> None:
     # 1. 邀请成员
     print("\n4.1 邀请成员...")
     member1 = manager.invite_member(
-        tenant_id=tenant_id, email="admin@test.com", role="admin", invited_by="user_001",
+        tenant_id=tenant_id,
+        email="admin@test.com",
+        role="admin",
+        invited_by="user_001",
     )
     print(f"✅ 成员邀请成功: {member1.email}")
     print(f"   - ID: {member1.id}")
@@ -171,7 +179,10 @@ def test_member_management(tenant_id: str) -> None:
     print(f"   - 权限: {member1.permissions}")
 
     member2 = manager.invite_member(
-        tenant_id=tenant_id, email="member@test.com", role="member", invited_by="user_001",
+        tenant_id=tenant_id,
+        email="member@test.com",
+        role="member",
+        invited_by="user_001",
     )
     print(f"✅ 成员邀请成功: {member2.email}")