Support token_endpoint_auth_signing_alg_values_supported

[josephdecock]

Add DiscoveryDocumentResponse.TokenEndpointAuthenticationSigningAlgorithmsSupported

This discovery document property is required by the FAPI 2.0 profile. Adding strongly typed support for it makes building conformant implementations easier.

[Copilot]

Pull Request Overview

Adds support for the token_endpoint_auth_signing_alg_values_supported discovery property by introducing a new constant and response property, updating test fixtures, and extending existing tests.

• Introduce TokenEndpointAuthenticationSigningAlgorithmsSupported in OidcConstants and DiscoveryDocumentResponse.
• Add the new signing-algorithms field to the JSON fixture and adjust discovery tests.
• Update the public API verification snapshot to include the new constant.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
identity-model/test/IdentityModel.Tests/documents/discovery.json	Add new signing-alg field and several endpoint properties (duplicate key present)
identity-model/test/IdentityModel.Tests/Verifications/PublicApiVerificationTests.VerifyPublicApi.verified.txt	Update snapshot for new constant (contains an unintended duplicate)
identity-model/test/IdentityModel.Tests/HttpClientExtensions/DiscoveryExtensionsTests.cs	Add assertions for the new signing algorithms and other endpoints
identity-model/src/IdentityModel/OidcConstants.cs	Define the new constant for signing algorithms
identity-model/src/IdentityModel/Client/Messages/DiscoveryDocumentResponse.cs	Expose the new signing-algorithms property

Comments suppressed due to low confidence (2)

identity-model/test/IdentityModel.Tests/Verifications/PublicApiVerificationTests.VerifyPublicApi.verified.txt:405

• The short-named constant TokenEndpointAuthSigningAlgorithmsSupported duplicates the newly added TokenEndpointAuthenticationSigningAlgorithmsSupported. Remove the obsolete entry to align the snapshot with the actual public API.

public const string TokenEndpointAuthSigningAlgorithmsSupported = "token_endpoint_auth_signing_alg_values_supported";

identity-model/test/IdentityModel.Tests/documents/discovery.json:15

• Duplicate JSON property 'end_session_endpoint' detected. Remove the redundant entry to prevent parsing conflicts and ensure a valid discovery document.

"end_session_endpoint": "https://demo.identityserver.io/connect/endsession"

[Copilot]

Pull Request Overview

This PR adds support for the new "token_endpoint_auth_signing_alg_values_supported" discovery document property required by the FAPI 2.0 profile. Key changes include the update of the discovery.json file with new endpoints and supported algorithms, the addition of a corresponding public API property, and expanded tests to verify the updated discovery document.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
identity-model/test/IdentityModel.Tests/documents/discovery.json	Adjusted discovery document with new endpoints and added signing algorithms property; however, a duplicate key for "end_session_endpoint" was introduced.
identity-model/test/IdentityModel.Tests/Verifications/PublicApiVerificationTests.VerifyPublicApi.verified.txt	Added new public API property for token endpoint authentication signing algorithms.
identity-model/test/IdentityModel.Tests/HttpClientExtensions/DiscoveryExtensionsTests.cs	Expanded tests to verify all endpoints and supported algorithms including the new signing algorithms.
identity-model/src/IdentityModel/Client/Messages/DiscoveryDocumentResponse.cs	Introduced a strongly typed property for token endpoint authentication signing algorithms.