Follow-ups for passkey support in ASP.NET Core Identity

[MackinnonBuck]

#62112 adds support for passkeys in ASP.NET Core Identity and extends the Blazor Web App template to support passkey management and authentication. However, there are some follow-up items we should consider:

• Enable WebAuthn conformance testing in CI
  • There's currently a project in this repo that can be run against the FIDO2 Conformance Test tool, but the tool itself is proprietary and doesn't have a CLI. We should consider writing our own solution that performs similar validations to the conformance testing tool.
• Determine how to best help customers migrate their databases to include passkeys
• Update scaffolding to include passkey support
• Support passwordless account creation
• Support conditional create to allow the user to seamlessly upgrade a password to a passkey after signing in
• Use the signals API to, e.g., inform the authenticator when a passkey was revoked so it doesn't get presented to the user as an option when signing in
• Make it easy to configure well-known passkey endpoints so that authenticators can automatically upgrade passwords to passkeys without requiring the customer to visit the site
• Update MapIdentityApi() to add endpoints for passkeys
• Update Microsoft.AspNetCore.Identity.UI to support the same passkey UI that got added to the Blazor Web App template

[abergs]

This issue tracks the considerations I raised here. Since my comment also adressess the API proposal I'll leave it be for now.

[mguinness]

I had made this comment in the API proposal #62287, but it might be more appropriate here.

Are there plans to integrate the new passkey support into the MapIdentityApi endpoints?