Add CLI Schema Option for `System.CommandLine`

[Flash0ver]

Summary

Add System.CommandLine Option for .NET CLI Schema via --cli-schema.

Remarks

• based on: Initial scaffolding for CLI introspection #2

The .NET CLI added CLI introspection with --cli-schema in the .NET 10 SDK.

Features

• Add a public API that adds an Option<bool> to System.CommandLine applications
  • Option<bool> should be recursive, to allow to JSONify the CLI command tree for the invoked command or subcommand
  • Option<bool> should be hidden, to not show in the help output
• Might accept optional JSON-Serializer options
• If there is a difference in the format of the output between .NET 10 and the upcoming .NET 11
  • then add a (required/optional) parameter as an enum to select the version
• Should be Trim-friendly and AOT-compatible, or have an overload that is
• Use System.Text.Json to output the JSON representation
  • target frameworks without built-in support as part of the shared framework should use the System.Text.Json NuGet package
• Use StringSyntaxAttribute.Json for testing
• Add Benchmarks for relevant public members
• Set appropriate <TargetFrameworks> for the Library
  • use multi-targeting for the Test project
• Ensure to be callable/invocable from C#, F#, and Visual Basic

Example

See: https://learn.microsoft.com/dotnet/core/whats-new/dotnet-10/sdk#cli-introspection-with---cli-schema

See also

• System.CommandLine repository: https://github.com/dotnet/command-line-api
• System.CommandLine documentation: https://learn.microsoft.com/dotnet/standard/commandline/
• System.Text.Json documentation: https://learn.microsoft.com/dotnet/standard/serialization/system-text-json/overview
• Trimming: https://learn.microsoft.com/dotnet/core/deploying/trimming/trim-self-contained
• Native AOT: https://learn.microsoft.com/dotnet/core/deploying/native-aot
• .NET SDK/CLI repository: https://github.com/dotnet/sdk