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.
Align ConfigManager with DataSync's per-file pipeline format (pipeline.*.json)
by reusing EtlPipelineConfig types directly, eliminating duplicate models and
simplifying the codebase. Removes ~3200 lines of obsolete code.