New Operation — Development skill for Claude Code

Add a new geometric operation to brepjs.

Workflow

1. Ask the user what the operation does and which module it belongs to
2. Read src//README.md for patterns and gotchas
3. Read an existing *Fns.ts in that module as a template (src/topology/booleanFns.ts is the canonical reference)
4. Implement following the template pattern:
   • Validate inputs → err(validationError(...))
   • Call getKernel().method(shape.wrapped); never access .wrapped methods directly
   • Cast with