Re-introduce JetBrains.Annotations; mark outer-layer assemblies [PublicAPI] - #6

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/setup-dotnet@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

'ServicePointManager' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead. Settings on ServicePointManager no longer affect SslStream or HttpClient.' (https://aka.ms/dotnet-warnings/SYSLIB0014)

'DockerBuildxCreateSettings.Config' hides inherited member 'DockerOptionsBase.Config'. Use the new keyword if hiding was intended.

'DockerConfigCreateSettings.Config' hides inherited member 'DockerOptionsBase.Config'. Use the new keyword if hiding was intended.

'DockerServiceCreateSettings.Config' hides inherited member 'DockerOptionsBase.Config'. Use the new keyword if hiding was intended.

'HelmUpgradeSettings.Set' hides inherited member 'Options.Set(string, object)'. Use the new keyword if hiding was intended.

'HelmTemplateSettings.Set' hides inherited member 'Options.Set(string, object)'. Use the new keyword if hiding was intended.

'HelmLintSettings.Set' hides inherited member 'Options.Set(string, object)'. Use the new keyword if hiding was intended.

'HelmInstallSettings.Set' hides inherited member 'Options.Set(string, object)'. Use the new keyword if hiding was intended.

The field 'Telemetry.s_confirmedVersion' is never used