All acceptance criteria PASS - tooltips already implemented in inspector:
- Single shared tooltip div with correct CSS styling
- Event delegation via setupTooltips() in app.js
- Immediate appearance (<50ms) via hidden attribute, no transitions
- Reads data-* attributes (text, font, confidence, bbox, etc.)
- Edge-aware positioning (repositions near viewport edges)
- XSS-safe via textContent rendering
- Works in both single-view and comparison modes
No code changes required - feature was already implemented.
