Backend: merge strategy — category defaults are applied as baseline
(ai_generated=0), AI impacts override/extend them (ai_generated=1).
All N category defaults appear in the impacts list; AI covers them
explicitly with event-specific score/direction adjustments.
Prompt: instruct AI to cover ALL default instruments.
Frontend: remove default impact chips under category selector —
they now appear directly in the instrument impacts list.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>