linuxchata/fido2

AI Summary: The `AttestationFidoMetadataServiceValidator` class is not correctly propagating the `cancellationToken` to its underlying `IMetadataCachedService` implementations. This prevents proper cancellation of operations within the cached service when invoked via the validator.

AI Summary: Refactor the `AttestationObjectValidator` class to make the logic for step 20 (Metadata Service verification) an extension point. This involves creating a separate class or interface for this specific logic and allowing developers to plug in their own implementations, improving flexibility and maintainability.

AI Summary: The task is to debug and fix an AccessViolationException in the `ConvertExtensions.FromBase64Url` method within a FIDO2 authentication library for .NET. The exception occurs when using Japanese Kanji characters (田中倫) as a user ID. The solution likely involves handling multi-byte character encoding (e.g., using UTF8), potentially limiting the user ID length, and expanding unit tests to cover a wider range of character sets.

AI Summary: Add a `LastUsed` property to the existing credential data model within the FIDO2 authentication library for .NET. This property will track the last time a specific credential was used for authentication.