security: P3 — 插件隔离默认开启 + SenSuDB 注册 + 审计日志

- plugins.isolation 默认 true (生产环境进程隔离)
- main.py 注册 SenSuDB 服务
- WebPanelManager 注入 sensu_db 到 app context
- 文件删除/写入操作写入审计日志 (audit_log 表)
- 修复 Session 持久化所需的数据库依赖

Co-Authored-By: Claude <noreply@anthropic.com>

services/web_panel/manager.py

@@ -33,6 +33,7 @@ class WebPanelManager:
         app['service_manager'] = self.sm
         app['auth_service'] = self.sm.get_service("auth")
         app['log_service'] = self.sm.get_service("log")
+        app['sensu_db'] = self.sm.get_service("sensu_db")
         app['panel_config'] = {
             'username': self.panel_user,
             'password': self.panel_pass,