Enterprise security manager [Public Preview]

### Value Prop

The new enterprise security manager role is designed to give your AppSec team comprehensive oversight across your entire enterprise—streamlining security management for large-scale organizations. Rather than manually configuring security settings for each individual organization, this role enables a single, centralized team to enforce security policies, monitor alerts, and access critical security data across all organizations in one unified view.

Additionally, this is a game-changer for GHES customers, who often manage security across dozens or even hundreds of organizations. By eliminating the need to set up security managers for each organization individually, the enterprise security manager role allows your team to oversee security operations across all organizations in the enterprise in just a few clicks—delivering faster, more consistent protection at scale.

### Expected Outcome

Our enterprise customers have expressed a more streamlined way to empower their security-focused teams without the added complexity of adding a security manager team to each organization. Moreover, these teams often require access to enterprise-level policies and security settings, which traditionally have been reserved for the enterprise owner or granted only partially. This new role addresses these needs by providing:

* Simplified, centralized access management across all organizations with just a few clicks.
* Expanded permissions that encompass both organization-level and enterprise-level oversight and control.

此路线图 issue 未确定任何实现文件、测试或入口点。首先明确企业安全管理器跨组织所需的权限和范围，然后定义实现和验证的位置；完成的标准是该角色提供所述的集中式企业级和组织级访问权限。

由索引模型根据 Issue 内容生成。