Static Web Apps identity.7 returns 401 during Entra authentication across independent resources

With reference to the [Microsoft-confirmed identity.7 incident](https://learn.microsoft.com/en-nz/answers/questions/5860048/we-are-having-some-issues-with-the-built-in-auth-f). I am seeing a similar issue. The key evidence is:

- Original SWA and an independent Standard replacement both failed at /.auth/login/aad/callback.
- They used different regions, hostnames, Entra registrations and credentials.
- A clean Free-tier app with no SchoolFlow code also failed during built-in authentication.
- All three resources were routed through identity.7.azurestaticapps.net.
- The application never loaded, so the failure occurred before our roles source or application authorization.

Can you confirm the incident and reroute the affected SWA resources to a healthy identity backend?

Start with the linked Microsoft-confirmed identity.7 incident and reproduce the failure at /.auth/login/aad/callback using the reported independent Static Web Apps resources. Confirm that authentication fails before the application loads and that the affected resources are routed through identity.7.azurestaticapps.net; done means the resources authenticate successfully through a healthy identity backend.

Written by the indexing model from the issue text.