Generate ITenantScope for tenant-aware .Biz.cs entities

[Copilot]

EntityBuilder already injects TenantInterceptor when a table contains TenantId, but generated business classes did not also implement ITenantScope. This change aligns the generated type declaration with the existing interceptor behavior for multi-tenant entities.

• Generator behavior

  • Update XCode/Code/EntityBuilder.cs so GetBaseClass() appends ITenantScope only for business-class generation (.Biz.cs) when the table has a TenantId column.
  • Keep matching case-insensitive.
  • Avoid duplicating ITenantScope if it is already present in the configured base/interface list.
  • Leave data-class generation (.cs) unchanged.

• Generated fixtures

  • Refresh affected generated business snapshots for tenant-aware entities:
    • 部门.Biz.cs
    • 角色.Biz.cs
    • 租户关系.Biz.cs

• Focused coverage

  • Add a targeted generator test covering:
    • tenant-aware business entity => Entity<T>, ITenantScope
    • non-tenant data entity => no automatic ITenantScope

Example generated declaration:

public partial class Role : Entity<Role>, ITenantScope
{
    static Role()
    {
        Meta.Interceptors.Add<TenantInterceptor>();
    }
}

• Fixes [Feature] XCodeTool 自动生成多租户表时，Biz.cs 应默认实现 ITenantScope 接口 #96