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 service for auto-discovering configuration file locations. The
service searches in prioritized order:
1. JDESCOPING_CONFIG_PATH environment variable
2. Same directory as executable
3. ../JdeScoping.Host/ relative to executable
4. User config directory (~/.jdescoping on Unix, %LOCALAPPDATA%\JdeScoping on Windows)
Includes 9 unit tests covering all search locations, priority order,
edge cases (missing directory, missing appsettings.json), and
cancellation token support.