Add options validation support to cli hosting and some minor changes for running the CliHost

[darthsharp]

No description provided.

[Copilot]

Pull request overview

This PR adds support for command options validation in the CLI hosting framework and introduces a new RunMainAsync method for direct integer exit code return. The implementation allows commands to implement IOptionsValidation interface for custom validation logic with automatic validation execution when enabled.

Key changes:

• Added options validation support via IOptionsValidation interface and OptionsValidationResult class
• Introduced UseValidation() method on ICliHostBuilder to enable/disable validation
• Added RunMainAsync() convenience method to ICliHost for returning exit codes directly as integers

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
source/Cli/CreativeCoders.Cli.Core/IOptionsValidation.cs	New interface for command options validation
source/Cli/CreativeCoders.Cli.Core/OptionsValidationResult.cs	New class to represent validation results with status and messages
source/Cli/CreativeCoders.Cli.Core/CommandResult.cs	Added constructors for convenient exit code initialization
source/Cli/CreativeCoders.Cli.Hosting/ICliHost.cs	Added RunMainAsync method for direct integer exit code return
source/Cli/CreativeCoders.Cli.Hosting/ICliHostBuilder.cs	Added UseValidation method to enable/disable options validation
source/Cli/CreativeCoders.Cli.Hosting/DefaultCliHost.cs	Implemented validation logic, RunMainAsync method, and added CliHostSettings class
source/Cli/CreativeCoders.Cli.Hosting/DefaultCliHostBuilder.cs	Implemented UseValidation method to configure validation settings
source/Cli/CreativeCoders.Cli.Hosting/Exceptions/CliCommandOptionsInvalidException.cs	New exception type for invalid command options
source/Cli/CreativeCoders.Cli.Hosting/CliExitCodes.cs	Added CommandOptionsInvalid exit code constant
tests/CreativeCoders.Cli.Tests/Hosting/DefaultCliHostTests.cs	Added comprehensive tests for validation scenarios and RunMainAsync
tests/CreativeCoders.Cli.Tests/Hosting/DefaultCliHostBuilderTests.cs	Added tests for UseValidation configuration

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[Copilot]

The assertion "Should().NotBe(true)" is an indirect way of checking that validation is disabled. This could pass if settings is null or if UseValidation is false. Consider being more explicit: check if settings is null OR if it exists, verify that UseValidation is explicitly false. This would make the test intent clearer and distinguish between "settings not added" versus "settings added with validation disabled".

Suggested change

	settings?.UseValidation
	.Should().NotBe(true);
	if (settings == null)
	{
	settings.Should().BeNull();
	}
	else
	{
	settings.UseValidation.Should().BeFalse();
	}