Extract shared models, services, and application logic into
JdeScoping.ConfigManager.Core library. Add JdeScoping.ConfigManager.Cli
console app with validate, test-connection, and secret commands using
System.CommandLine. UI project now references Core for platform-agnostic
functionality while retaining Avalonia-specific dialog and clipboard services.
Add comprehensive tests for services (ConnectionTestService, RuntimeConfigValidation),
ViewModels (PipelineEditor, dialogs, transformers), and Avalonia headless UI tests
for views and forms.