VSM Workshop - Development Rules

# VSM Workshop - Development Rules

## Data Validation

Always validate step metrics:
- Process Time (PT) must be ≤ Lead Time (LT)
- %C&A (Percent Complete & Accurate) must be between 0-100
- Queue sizes and batch sizes must be ≥ 0
- Time values must be in minutes

## State Management

Preserve Zustand store patterns:
- Use store hooks directly in components (no prop drilling)
- Define actions as store methods
- Keep derived values as computed selectors
- Follow the established store structure in `src/stores/`

## Display Formatting

Use `formatDuration` for time display:
- Input/storage: always in minutes
- Display: formatted based on magnitude (m, h, d)
- Import from `src/utils/formatting` or calculations module

## ReactFlow Integration

Maintain ReactFlow node structure:
- Nodes must have: `id`, `type`, `data`, `position`
- Custom node types in `src/components/canvas/nodes/`
- Edge types: `forward` (solid) or `rework` (dashed)
- Use data-testid attributes for testing

## Code Quality

- Always write tests before implementation (TDD)
- Use PropTypes for all React components
- Follow Prettier formatting (single quotes, no semicolons)
- Add JSDoc comments for utility functions