feat: Text callout annotations #41
Description
Summary
Add text callout boxes to explain code sections.
Motivation
Provide contextual explanations within the comparison image.
Implementation
- Add text boxes with configurable style
- Position boxes anywhere on panels
- Connect to code with lines
- Export includes callouts
Acceptance Criteria
- Add text callouts
- Position and resize callouts
- Callouts visible in export
- Edit/delete callouts
Story Points
5 points