Provides RobotLab::RactorWorkerPool — a pool of Ruby Ractor workers for executing CPU-bound, Ractor-safe tools in parallel. Includes RactorBoundary (deep-freeze utility for crossing Ractor boundaries), RactorJob/RactorJobError/RobotSpec (frozen data carriers), RactorMemoryProxy (shared Memory access from inside Ractors), and RactorNetworkScheduler (dependency-ordered pipeline across Ractors).