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.
Adds a new ConnectionStrings section to ConfigManager allowing users to manage
database connection strings with provider selection, connection testing, and
visual feedback for connection state.
Consolidate SecureStoreLockedFormView and SecureStoreUnlockedFormView into
a single SecureStoreInfoFormView that displays store status and metadata.
Simplifies MainWindowViewModel by removing redundant state management.
Also adds design docs for RegexTransformer feature.
Add comprehensive XML documentation (param/returns tags) across 132 source
files to improve IntelliSense and API discoverability. Include ConfigManager
design documents and implementation plans for phases 1-9.
Joseph Doherty