[WIP] Add unit tests for matchypatchy from tests branch

[Copilot]

• Inspect repository state, branches, and existing test setup
• Identify the minimal diff needed to bring tests branch unit tests onto the current work branch targeting dev
• Apply the focused test changes and any directly required supporting updates
• Run targeted validation for the affected tests
• Scan changed files for secrets and run CodeQL review
• Report progress with the final minimal change set