Added detailed documentation covering:
## System Overview
- Skill-based problem generation concept
- Core principle: difficulty based on required abacus techniques
- Integration with tutorial progression
## Skill Definitions
- Five complements (5-column operations)
- Ten complements (multi-column carrying)
- Basic operations hierarchy
## Technical Implementation
- TypeScript interfaces and skill sets
- Problem generation algorithm
- Validation process
## Editor Integration
- Practice step creation workflow
- UI components and skill selection
- Problem preview and validation
## Examples
- Configuration examples for different skill levels
- Implementation code samples
- Benefits for learners and educators
This serves as both developer reference and educator guide for
the skill-based practice problem generation system.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
