fix: auto-fix code issues (cron)

- 修复缺失导入: main.py 添加 AttributeTemplate 和 EntityAttribute 导入
- 修复裸异常捕获: 将 BaseException 改为具体异常类型
  - neo4j_manager.py: Exception
  - main.py: json.JSONDecodeError, ValueError, Exception
  - export_manager.py: AttributeError, TypeError, ValueError
  - localization_manager.py: ValueError, AttributeError
  - performance_manager.py: TypeError, ValueError
  - plugin_manager.py: OSError, IOError
- 修复部分行长度问题: security_manager.py 长行拆分

backend/performance_manager.py

@@ -234,7 +234,7 @@ class CacheManager:
         """估算缓存条目大小"""
         try:
             return len(json.dumps(value, ensure_ascii=False).encode("utf-8"))
-        except BaseException:
+        except (TypeError, ValueError):
             return 1024  # 默认估算
 
     def _evict_lru(self, required_space: int = 0) -> None: