Add an internal clipboard on the controller with undoable macro paste, and
Copy/Paste menu actions and shortcuts in the main window. Covered by a test.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Set up PyQt6 + QGraphicsView pipeline-editor skeleton, requirements,
pytest headless config, and the actionable implementation plan under
docs/plan.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>