Angular 20 update

[m-akinc]

Pull Request

🤨 Rationale

Fixes #2829

👩‍💻 Implementation

• Updated Angular dependencies to 20.3.15
• Updated to Angular-20-compatible eslint-config-angular version
• Updated forked Angular files in packages/angular-workspace/nimble-angular/thirdparty

🧪 Testing

Automated tests pass.

[m-akinc]

I temporarily did a manual major version bump to ensure no published version gets installed over these while validation testing.

Need to revert each package's version before submitting.

[jattasNI]

I did a quick manual scan of the Angular example app and everything looked unchanged 👍

Update looks good to me, just waiting to approve so I can take another look when the release train starts.

[jattasNI]

What's your policy for deciding whether to update the typescript version? I noticed that you'd bumped it for Angular 19 but not for 20. #2786.

In Angular's version compatibility table it says we could bump to 5.9.x if we wanted. But if our historic policy is to only upgrade when needed, I'm fine with keeping that.

[m-akinc]

Yes, I've typically not upgraded anything else significant (like typescript) unless I had to. If something stops working, it would be nice to have fewer things to have to consider.

[rajsite]

Agree that it shouldn't be done in the Angular upgrade PR unless absolutely necessary, but we should consider upgrading the TypeScript versions everywhere (i.e. including ni/fast) to be part of the Angular upgrade process (as follow-up PRs) so it's done consistently and since it is bounded by Angular.

[rajsite]

Looks like the thirdparty directory forks where a pain this time around. Thanks for the thorough approach, looks good!