feat(badges): add name property to badge models and mock

[jasonwoods-7]

• GitLab badges support an optional name field. Expose it on Badge, BadgeCreate and BadgeUpdate so callers can set and read it.
• Mock: store the name on Badge. Set it on create and update in the project and group badge clients.
• Mock: add a BadgeCollection.Add(name, linkUrl, imageUrl) overload. Keep the old Add(linkUrl, imageUrl) overload so existing callers still compile.
• Tests: cover name on create and update for project and group badges, in both the integration tests and the mock tests.

[msrouchou]

Thanks for the PR. A few points:

1. Mock Update ignores Name. ProjectBadgeClient.cs (badgeToUpdate.LinkUrl = badge.LinkUrl;) and GroupBadgeClient.cs need badgeToUpdate.Name = badge.Name; too, otherwise the mock drops the name on update and differs from the real API. Please match how LinkUrl and ImageUrl treat null, and add tests in NGitLab.Mock.Tests and GroupBadgeClientTests.
2. The description says the name is "required" in BadgeCollection.Add, but nothing validates it, and GitLab treats name as optional. Please fix the description, or add the check and drop the Is.Null assert.
3. Please check that BadgeCreate.Name and BadgeUpdate.Name are omitted from the JSON when null, instead of sending "name": null.

[jasonwoods-7]

It looks like Claude fixed everything except point 3 in your review. I asked about that and it said

No. I found no test that checks serialized request JSON.

• JsonConverterTests.cs only tests deserialization. It calls Serializer.Deserialize on JSON input.
• The only Serialize call in NGitLab.Tests is in Docker/GitLabDockerContainer.cs:389. It serializes test credentials, not request bodies.
• HttpRequestorTests.cs has no body or JSON checks.
• The Docker tests (ProjectBadgeClientTests, GroupBadgeClientTests) send real requests, so they never see the request JSON.

So nothing checks that a null Name is left out. That behavior comes only from Serializer.cs:23 (DefaultIgnoreCondition = WhenWritingNull).

I could add a small test that serializes BadgeCreate and BadgeUpdate with a null Name and asserts there is no "name" key. It would back up your reply on the null-omit review point. Do you want it?

Would you like that added?

[msrouchou]

Would you like that added?

nah it is fine, merging, thank you for the contribution.

[msrouchou]

released: https://github.com/ubisoft/NGitLab/releases#release-12.5.0