This commit introduces a comprehensive Role-Based Access Control (RBAC) system for TenantAtlas.
- Implements authentication via Microsoft Entra ID (OIDC).
- Manages authorization on a per-Suite-Tenant basis using a table.
- Follows a capabilities-first approach, using Gates and Policies.
- Includes a break-glass mechanism for platform superadmins.
- Adds policies for bootstrapping tenants and managing admin responsibilities.
