GA positive vs critical highlights toggle

# GA positive vs critical highlights toggle

Today the GA highlights what students should fix. Add a toggle to highlight what students did well — strengths, not just issues. Either mode can be on; or both.

## Problem

Students experiencing only negative highlights miss the motivation signal of "this part is working — keep doing this." Skilled human teachers balance both. The GA can do the same; it just isn't doing it today.

## Goals (rough)

- Toggle on/off for positive highlights and critical highlights independently.
- Default: critical on, positive off (matches today's behavior — preserve current expectations).
- Both signals share the highlight model, just differently colored.

## Non-goals

- Replacing the comments panel. Highlights complement comments; this isn't a redesign.

## Open questions

- [ ] Where does the toggle live — student-side, teacher-side, both? Probably teacher controls the default per-assignment, student can choose what they see while reviewing.
- [ ] Visual treatment: green for positive, red for critical? Color-blind considerations.

## Engineering handoff

Not ready. Idea-stage.