Spline import now uses SplineConverter (arc-based) so the configurable
precision parameter is obsolete. Removed the setting from the options
dialog, DxfImporter property, Settings files, and all callsites.
Hardcoded 200 as the sampling density for the intermediate point
evaluation that feeds into SplineConverter.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Move 43 root-level test files into feature-specific subdirectories
mirroring the main codebase structure: Geometry, Fill, BestFit, CutOffs,
CuttingStrategy, Engine, IO. Update namespaces to match folder paths.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
