feat: add export_ipc2581 tool (kicad-cli, with BOM column mapping)

New MCP tool `export_ipc2581` wrapping `kicad-cli pcb export ipc2581`:
precision, compression, standard version, units, and the five
--bom-col-* field mappings (internal id, mfg P/N, mfg, distributor P/N,
distributor) that control the BOM part data embedded in the IPC-2581
file — directly useful for MES/assembly imports that need a real
internal P/N rather than the description. Self-contained interface
handler reading the saved .kicad_pcb.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/tools/registry.ts

@@ -60,6 +60,7 @@ export const toolCategories: ToolCategory[] = [
       "export_gerber",
       "export_gerbers",
       "export_drill",
+      "export_ipc2581",
       "export_pdf",
       "export_svg",
       "export_3d",