fix: auto-fix code issues (cron)

- 修复裸异常捕获 (E722) - 改为具体异常类型
- 修复重复导入/字段定义问题
- 修复PEP8格式问题 (W291 trailing whitespace, E226, E741)
- 修复未使用变量 (F841)
- 修复变量名遮蔽 (F402)
- 修复未定义名称 (F821) - 添加 urllib.parse 导入
- 修复 f-string 缺少占位符 (F541)
- 修复模块级导入位置 (E402)
- 修复行尾空白和空行问题
- 优化代码结构，提升可读性

backend/tenant_manager.py

@@ -1,22 +1,4 @@
 
-class TenantLimits:
-    """租户资源限制常量"""
-    FREE_MAX_PROJECTS = 3
-    FREE_MAX_STORAGE_MB = 100
-    FREE_MAX_TRANSCRIPTION_MINUTES = 60
-    FREE_MAX_API_CALLS_PER_DAY = 100
-    FREE_MAX_TEAM_MEMBERS = 2
-    FREE_MAX_ENTITIES = 100
-    
-    PRO_MAX_PROJECTS = 20
-    PRO_MAX_STORAGE_MB = 1000
-    PRO_MAX_TRANSCRIPTION_MINUTES = 600
-    PRO_MAX_API_CALLS_PER_DAY = 10000
-    PRO_MAX_TEAM_MEMBERS = 10
-    PRO_MAX_ENTITIES = 1000
-    
-    UNLIMITED = -1
-
 """
 InsightFlow Phase 8 - 多租户 SaaS 架构管理模块
 
@@ -43,6 +25,25 @@ import logging
 logger = logging.getLogger(__name__)
 
 
+class TenantLimits:
+    """租户资源限制常量"""
+    FREE_MAX_PROJECTS = 3
+    FREE_MAX_STORAGE_MB = 100
+    FREE_MAX_TRANSCRIPTION_MINUTES = 60
+    FREE_MAX_API_CALLS_PER_DAY = 100
+    FREE_MAX_TEAM_MEMBERS = 2
+    FREE_MAX_ENTITIES = 100
+
+    PRO_MAX_PROJECTS = 20
+    PRO_MAX_STORAGE_MB = 1000
+    PRO_MAX_TRANSCRIPTION_MINUTES = 600
+    PRO_MAX_API_CALLS_PER_DAY = 10000
+    PRO_MAX_TEAM_MEMBERS = 10
+    PRO_MAX_ENTITIES = 1000
+
+    UNLIMITED = -1
+
+
 class TenantStatus(str, Enum):
     """租户状态"""
     ACTIVE = "active"           # 活跃
@@ -157,28 +158,6 @@ class TenantPermission:
     created_at: datetime
 
 
-class TenantLimits:
-    """租户资源限制常量"""
-    # Free 套餐限制
-    FREE_MAX_PROJECTS = 3
-    FREE_MAX_STORAGE_MB = 100
-    FREE_MAX_TRANSCRIPTION_MINUTES = 60
-    FREE_MAX_API_CALLS_PER_DAY = 100
-    FREE_MAX_TEAM_MEMBERS = 2
-    FREE_MAX_ENTITIES = 100
-    
-    # Pro 套餐限制
-    PRO_MAX_PROJECTS = 20
-    PRO_MAX_STORAGE_MB = 1000
-    PRO_MAX_TRANSCRIPTION_MINUTES = 600
-    PRO_MAX_API_CALLS_PER_DAY = 10000
-    PRO_MAX_TEAM_MEMBERS = 10
-    PRO_MAX_ENTITIES = 1000
-    
-    # Enterprise 套餐 - 无限制
-    UNLIMITED = -1
-
-
 class TenantManager:
     """租户管理器 - 多租户 SaaS 架构核心"""