New MCP tool `export_gencad` wrapping `kicad-cli pcb export gencad`: exposes define-var plus the flip-bottom-pads, unique-pins, unique-footprints, use-drill-origin and store-origin-coord flags. Self-contained interface handler reading the saved .kicad_pcb. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>