Refactor flat top-level statements into NestConsole class with Options and focused methods. Add support for passing .dxf files directly as input — auto-imports geometry via DxfImporter and creates a fresh nest with a plate when --size is specified. Supports three modes: nest-only, DXF-only (requires --size), and mixed nest+DXF. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>