- Drop Circle.ToArcFrom (zero-sweep problem), keep Circle in shape
and handle in ConvertShapeToMoves with full-circle ArcMove
- Use point-distance tolerance for Arc.SplitAt instead of angle
comparison to avoid wrap-around issues at 0/2pi
- Simplify SplitAt return types to non-nullable tuple
- Add ArgumentException guard in ReindexAt
- Add throw for unexpected entity types in ConvertShapeToMoves
- Document absolute coordinate convention and shared references
- Clarify variable names for both replacement sites
