Create a DI/scopes sample and exploratory compatibility matrix

[KlausLoeffelmann]

Objective

Build a sample with constructor-injected Forms, Designer-created UserControls/components, modal and modeless scopes, navigation, cancellation, and disposal diagnostics. Exercise C# and VB, Designer round trips, Classic/light/Dark Mode, Terminal Services, Windows on ARM, and slow hardware.

Completion guidance

• Keep the implementation focused on the objective while allowing the assignee to improve the approach based on research.
• Document important decisions, rejected alternatives, dependencies, and follow-up work.
• Add or update tests and documentation appropriate to the work.
• Verify locally and in CI where the task changes code or generated artifacts.